Surgical instruments with torsion spine drive arrangements

ABSTRACT

Surgical instruments with articulatable surgical end effectors and rotary driven flexible drive members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 63/057,430, entitled SURGICAL INSTRUMENTS WITH TORSION SPINE DRIVE ARRANGEMENTS, filed Jul. 28, 2020, of U.S. Provisional Patent Application Ser. No. 63/057,432, entitled ARTICULATION JOINT ARRANGEMENTS FOR SURGICAL INSTRUMENTS, filed Jul. 28, 2020, the disclosures of which are incorporated by reference herein in their entireties.

BACKGROUND

The present invention relates to surgical instruments and, in various arrangements, to surgical stapling and cutting instruments and staple cartridges for use therewith that are designed to staple and cut tissue. The surgical instruments may be configured for use in open surgical procedures, but have applications in other types of surgery, such as laparoscopic, endoscopic, and robotic-assisted procedures and may include end effectors that are articulatable relative to a shaft portion of the instrument to facilitate precise positioning within a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the various aspects are set forth with particularity in the appended claims. The described aspects, however, both as to organization and methods of operation, may be best understood by reference to the following description, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a surgical end effector portion of a surgical instrument in accordance with at least one aspect of the present disclosure;

FIG. 2 is a side view of the surgical end effector portion instrument of FIG. 1 in a closed orientation;

FIG. 3 is an end view of the surgical end effector of FIG. 2 ;

FIG. 4 is a top view of the surgical end effector of FIG. 2 ;

FIG. 5 is an exploded assembly view of a portion of the surgical instrument of FIG. 1 ;

FIG. 6 is an exploded assembly view of an elongate shaft assembly of the surgical instrument of FIG. 1 ;

FIG. 7 is another exploded assembly view of the elongate shaft assembly of FIG. 6 ;

FIG. 8 is an exploded assembly view of a firing system and a rotary drive system according to at least one aspect of the present disclosure;

FIG. 9 is a side view of a firing member and upper and lower flexible spine assemblies of the firing system in engagement with a rotary drive screw of the rotary drive system of FIG. 8 ;

FIG. 10 is a cross-sectional view of the firing member and upper and lower flexible spine assemblies of FIG. 9 ;

FIG. 11 is a side elevational view of the firing member and upper and lower flexible spine assemblies in engagement with the rotary drive screw of FIG. 9 ;

FIG. 12 is a cross-sectional end view of the surgical end effector of FIG. 4 taken along line 12-12 in FIG. 4 ;

FIG. 13 is an exploded perspective view of two adjacent upper vertebra members of the upper flexible spine assembly of FIG. 10 ;

FIG. 14 is an exploded perspective view of two adjacent lower vertebra members of the lower flexible spine assembly of FIG. 10 ;

FIG. 15 is a top view of a firing member and upper and lower flexible spine assemblies in engagement with the rotary drive screw of FIG. 9 ;

FIG. 16 is a perspective view of a CV drive shaft assembly of the rotary drive system of FIG. 8 in an articulated orientation;

FIG. 17 is a perspective view of the firing system of FIG. 8 in driving engagement with the CV drive shaft assembly of FIG. 16 in accordance with at least one aspect of the present disclosure;

FIG. 18 is a perspective view of a drive joint of the CV drive shaft assembly of FIG. 16 ;

FIG. 19 is a cross-sectional view of a portion of the surgical instrument of FIG. 4 taken along line 19-19 in FIG. 4 ;

FIG. 20 is a partial perspective view of a proximal end portion of the surgical end effector and portions of the firing system and the rotary drive system of the surgical instrument of FIG. 1 ;

FIG. 21 is a perspective view of the rotary drive system of the surgical instrument of FIG. 1 in driving engagement with the firing system thereof in accordance with at least one aspect of the present disclosure;

FIG. 22 is an exploded perspective view of the rotary drive screw and thrust bearing arrangement of the firing system of FIG. 21 ;

FIG. 23 is a side view of the rotary drive screw of FIG. 22 ;

FIG. 24 is a partial cross-sectional side view of a portion of the lower flexible spine assembly and a portion of the firing member of FIG. 21 in driving engagement with a portion of the rotary drive screw;

FIG. 25 is a perspective view of the firing member in a home or starting position within the surgical end effector of the surgical instrument of FIG. 1 ;

FIG. 26 is a side view illustrating the upper flexible spine assembly and the lower flexible spine assembly of FIG. 21 in driving engagement with the rotary drive screw after the firing member has been driven distally from a home or starting position;

FIG. 27 is a partial cross-sectional perspective view of a portion of the surgical end effector, firing system and rotary drive system of the surgical instrument of FIG. 1 according to at least one aspect of the present disclosure with an outer elastomeric joint assembly of an articulation joint omitted for clarity;

FIG. 28 is another partial perspective view of a portion of the surgical end effector, firing system and rotary drive system of FIG. 27 with an outer elastomeric joint assembly of an articulation joint and portions of the elongate shaft assembly omitted for clarity;

FIG. 29 is a top view of the surgical end effector of FIG. 27 articulated in a first direction relative to a portion of the elongate shaft assembly in accordance with at least one aspect of the present disclosure;

FIG. 30 is a side view of the surgical end effector of FIG. 29 articulated in another direction relative to a portion of the elongate shaft assembly in accordance with at least one aspect of the present disclosure;

FIG. 31 is a perspective view of the surgical end effector of FIG. 29 articulated in multiple planes with respect to a portion of the elongate shaft assembly in accordance with at least one aspect of the present disclosure;

FIG. 32 is a side elevational view of a portion of another surgical instrument that employs another outer elastomeric joint assembly in accordance with at least one aspect of the present disclosure;

FIG. 33 is a partial cross-sectional perspective view of the surgical instrument of FIG. 32 ;

FIG. 34 is a perspective view of a portion of the outer elastomeric joint assembly of FIG. 32 ;

FIG. 35 is a cross-sectional end view of a portion of the surgical instrument of FIG. 19 taken along lines 35-35 in FIG. 19 ;

FIG. 36 is a cross-sectional end view of a portion of the surgical instrument of FIG. 19 taken along lines 36-36 in FIG. 19 ;

FIG. 37 is a partial cross-sectional view of a portion of an anvil cap and an upper vertebra member of the surgical instrument of FIG. 19 in accordance with at least one aspect of the present disclosure;

FIG. 38 is a side view of a portion of the surgical end effector of the surgical instrument of FIG. 19 with an anvil thereof in an open position in accordance with at least one aspect of the present disclosure and with portions of the surgical end effector omitted for clarity;

FIG. 39 is a partial cross-sectional side view of the surgical end effector of FIG. 38 with the anvil in an open position and the firing member in the home or starting position in accordance with at least one aspect of the present disclosure;

FIG. 40 is another partial cross-sectional side view of the surgical end effector of FIG. 39 with the anvil in a partially closed position;

FIG. 41 is another partial cross-sectional side view of the surgical end effector of FIG. 39 with the anvil in a fully closed position and the firing member distally advancing through the surgical end effector;

FIG. 42 is a partial side elevational view of the surgical end effector of FIG. 19 with portions thereof omitted for clarity to illustrate the anvil opening springs applying an opening motion to the anvil and with the firing member in a home or starting position;

FIG. 43 is another partial side view of the surgical end effector of FIG. 42 , after the firing member has moved proximally a short distance to apply a quick closure motion to the anvil for grasping purposes;

FIG. 44 is a cross-sectional view of the surgical end effector of FIG. 19 with the jaws thereof in a closed position and the firing member thereof in a proximal-most position;

FIG. 45 is another cross-sectional view of the surgical end effector of FIG. 44 , after the firing member has been distally advanced to the ending position within the surgical end effector;

FIG. 46 is a perspective view of a portion of another surgical instrument;

FIG. 47 is a side elevational view of a surgical end effector of the surgical instrument of FIG. 46 , with the jaws thereof in an open position;

FIG. 48 is another side view of the surgical end effector of FIG. 48 with the jaws thereof in a closed position;

FIG. 49 is an exploded assembly view of a portion of the surgical instrument of FIG. 46 ;

FIG. 50 is a perspective view of a firing member and portions of an upper flexible spine assembly and a lower flexible spine assembly of a firing system of the surgical instrument of FIG. 46 ;

FIG. 51 is a cross-sectional side view of the portions of the firing system depicted in FIG. 50 ;

FIG. 52 is a partial exploded assembly view of the upper flexible spine assembly and lower flexible spine assembly depicted in FIG. 51 ;

FIG. 53 is a partial cross-sectional end view of an upper portion of the firing member depicted in FIG. 50 ;

FIG. 54 is a cross-sectional end view of the surgical end effector of the surgical instrument of FIG. 46 , with the jaws thereof in a closed position;

FIG. 55 is a view of a proximal face of an annular rib member of a movable exoskeleton assembly of the surgical instrument of FIG. 46 ;

FIG. 56 is a view of a distal face of the annular rib member of FIG. 55 ;

FIG. 57 is a side view of the annular rib member of FIGS. 55 and 56 ;

FIG. 58 is a partial cross-sectional view of a portion of the surgical instrument of FIG. 46 ;

FIG. 59 is a side view of an articulation joint of the surgical instrument of FIG. 46 when the surgical end effector thereof is in an unarticulated position;

FIG. 60 is another side view of the articulation joint of FIG. 59 when the surgical end effector is in an articulated position;

FIG. 61 is partial perspective view of a portion of the surgical instrument of FIG. 46 with the surgical end effector omitted for clarity;

FIG. 62 is another partial perspective view of a portion of the surgical instrument of FIG. 46 ;

FIG. 63 is another partial perspective view of a portion of the surgical instrument of FIG. 46 ;

FIG. 64 is a perspective view of a CV drive shaft assembly and a portion of the elongate shaft assembly of the surgical instrument of FIG. 46 ;

FIG. 65 is another perspective view of the CV drive shaft assembly and elongated shaft assembly of FIG. 64 with a drive cover embodiment installed around the CV drive shaft assembly;

FIG. 66 is another perspective view of the CV drive shaft assembly and elongated shaft assembly of FIG. 64 with another drive cover embodiment installed around the CV drive shaft assembly;

FIG. 67 is another perspective view of the CV drive shaft assembly and elongated shaft assembly of FIG. 64 with another drive cover embodiment installed around the CV drive shaft assembly;

FIG. 68 is a side view of a portion of the firing system of the surgical instrument of FIG. 46 with the drive cover of FIG. 67 installed around the CV drive shaft assembly; and

FIG. 69 is another side view of the portion of the firing system and drive cover of FIG. 68 .

DETAILED DESCRIPTION

Applicant of the present application owns the following U.S. Patent Applications that were filed on Jun. 28, 2021 and which are each herein incorporated by reference in their respective entireties:

-   -   U.S. patent application Ser. No. 17/360,139, entitled SURGICAL         INSTRUMENTS WITH FIRING MEMBER CLOSURE FEATURES, now U.S. Patent         Application Publication No. 2022-0031322;     -   U.S. patent application Ser. No. 17/360,149, entitled SURGICAL         INSTRUMENTS WITH SEGMENTED FLEXIBLE DRIVE ARRANGEMENTS, now U.S.         Patent Application Publication No. 2022-0031314;     -   U.S. patent application Ser. No. 17/360,162, entitled SURGICAL         INSTRUMENTS WITH FLEXIBLE BALL CHAIN DRIVE ARRANGEMENTS, now         U.S. Patent Application Publication No. 2022-0031319;     -   U.S. patent application Ser. No. 17/360,176, entitled SURGICAL         INSTRUMENTS WITH DOUBLE SPHERICAL ARTICULATION JOINTS WITH         PIVOTABLE LINKS, now U.S. Patent Application Publication No.         2022-0031345;     -   U.S. patent application Ser. No. 17/360,192 entitled SURGICAL         INSTRUMENTS WITH DOUBLE PIVOT ARTICULATION JOINT ARRANGEMENTS,         now U.S. Patent Application Publication No. 2022-0031350;     -   U.S. patent application Ser. No. 17/360,197, entitled SURGICAL         INSTRUMENTS WITH COMBINATION FUNCTION ARTICULATION JOINT         ARRANGEMENTS, now U.S. Patent Application Publication No.         2022-0031323;     -   U.S. patent application Ser. No. 17/360,199, entitled METHOD OF         OPERATING A SURGICAL INSTRUMENT, now U.S. Patent Application         Publication No. 2022-0031315;     -   U.S. patent application Ser. No. 17/360,211, entitled SURGICAL         INSTRUMENTS WITH DUAL SPHERICAL ARTICULATION JOINT ARRANGEMENTS,         now U.S. Patent Application Publication No. 2022-0031324;     -   U.S. patent application Ser. No. 17/360,220, entitled SURGICAL         INSTRUMENTS WITH FLEXIBLE FIRING MEMBER ACTUATOR CONSTRAINT         ARRANGEMENTS, now U.S. Patent Application Publication No.         2022-0031320;     -   U.S. patent application Ser. No. 17/360,244, entitled         ARTICULATABLE SURGICAL INSTRUMENTS WITH ARTICULATION JOINTS         COMPRISING FLEXIBLE EXOSKELETON ARRANGEMENTS, now U.S. Patent         Application Publication No. 2022-0031346; and     -   U.S. patent application Ser. No. 17/360,249, entitled SURGICAL         INSTRUMENTS WITH DIFFERENTIAL ARTICULATION JOINT ARRANGEMENTS         FOR ACCOMMODATING FLEXIBLE ACTUATORS, now U.S. Patent         Application Publication No. 2022-0031351.

Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. Well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. The reader will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and illustrative. Variations and changes thereto may be made without departing from the scope of the claims.

The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a surgical system, device, or apparatus that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Likewise, an element of a system, device, or apparatus that “comprises,” “has,” “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features.

The terms “proximal” and “distal” are used herein with reference to a clinician manipulating the handle portion of the surgical instrument. The term “proximal” refers to the portion closest to the clinician and the term “distal” refers to the portion located away from the clinician. It will be further appreciated that, for convenience and clarity, spatial terms such as “vertical”, “horizontal”, “up”, and “down” may be used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and/or absolute.

References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Thus, the term “or” should generally be understood to mean “and/or”, etc.

Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated herein, and each separate value within such a range is incorporated into the disclosure as if it were individually recited herein. The words “about,” “approximately” or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Similarly, words of approximation such as “approximately” or “substantially” when used in reference to physical characteristics, should be construed to contemplate a range of deviations that would be appreciated by one of ordinary skill in the art to operate satisfactorily for a corresponding use, function, purpose or the like.

The use of any and all examples, or exemplary language (“e.g.,” “such as,” or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the embodiments.

Various exemplary devices and methods are provided for performing laparoscopic and minimally invasive surgical procedures. However, the reader will readily appreciate that the various methods and devices disclosed herein can be used in numerous surgical procedures and applications including, for example, in connection with open surgical procedures. As the present Detailed Description proceeds, the reader will further appreciate that the various instruments disclosed herein can be inserted into a body in any way, such as through a natural orifice, through an incision or puncture hole formed in tissue, etc. The working portions or end effector portions of the instruments can be inserted directly into a patient's body or can be inserted through an access device that has a working channel through which the end effector and elongate shaft of a surgical instrument can be advanced.

It is common practice during various laparoscopic surgical procedures to insert a surgical end effector portion of a surgical instrument through a trocar that has been installed in the abdominal wall of a patient to access a surgical site located inside the patient's abdomen. In its simplest form, a trocar is a pen-shaped instrument with a sharp triangular point at one end that is typically used inside a hollow tube, known as a cannula or sleeve, to create an opening into the body through which surgical end effectors may be introduced. Such arrangement forms an access port into the body cavity through which surgical end effectors may be inserted. The inner diameter of the trocar's cannula necessarily limits the size of the end effector and drive-supporting shaft of the surgical instrument that may be inserted through the trocar.

Regardless of the specific type of surgical procedure being performed, once the surgical end effector has been inserted into the patient through the trocar cannula, it is often necessary to move the surgical end effector relative to the shaft assembly that is positioned within the trocar cannula in order to properly position the surgical end effector relative to the tissue or organ to be treated. This movement or positioning of the surgical end effector relative to the portion of the shaft that remains within the trocar cannula is often referred to as “articulation” of the surgical end effector. A variety of articulation joints have been developed to attach a surgical end effector to an associated shaft in order to facilitate such articulation of the surgical end effector. As one might expect, in many surgical procedures, it is desirable to employ a surgical end effector that has as large a range of articulation as possible.

Due to the size constraints imposed by the size of the trocar cannula, the articulation joint components must be sized so as to be freely insertable through the trocar cannula. These size constraints also limit the size and composition of various drive members and components that operably interface with the motors and/or other control systems that are supported in a housing that may be handheld or comprise a portion of a larger automated system. In many instances, these drive members must operably pass through the articulation joint to be operably coupled to or operably interface with the surgical end effector. For example, one such drive member is commonly employed to apply articulation control motions to the surgical end effector. During use, the articulation drive member may be unactuated to position the surgical end effector in an unarticulated position to facilitate insertion of the surgical end effector through the trocar and then be actuated to articulate the surgical end effector to a desired position once the surgical end effector has entered the patient.

Thus, the aforementioned size constraints form many challenges to developing an articulation system that can effectuate a desired range of articulation, yet accommodate a variety of different drive systems that are necessary to operate various features of the surgical end effector. Further, once the surgical end effector has been positioned in a desired articulated position, the articulation system and articulation joint must be able to retain the surgical end effector in that locked position during the actuation of the end effector and completion of the surgical procedure. Such articulation joint arrangements must also be able to withstand external forces that are experienced by the end effector during use.

A variety of surgical end effectors exist that are configured to cut and staple tissue. Such surgical end effectors commonly include a first jaw feature that supports a surgical staple cartridge and a second jaw that comprises an anvil. The jaws are supported relative to each other such that they can move between an open position and a closed position to position and clamp target tissue therebetween. Many of these surgical end effectors employ an axially moving firing member. In some end effector designs, the firing member is configured to engage the first and second jaws such that as the firing member is initially advanced distally, the firing member moves the jaws to the closed position. Other end effector designs employ a separate closure system that is independent and distinct from the system that operates the firing member.

The staple cartridge comprises a cartridge body. The cartridge body includes a proximal end, a distal end, and a deck extending between the proximal end and the distal end. In use, the staple cartridge is positioned on a first side of the tissue to be stapled and the anvil is positioned on a second side of the tissue. The anvil is moved toward the staple cartridge to compress and clamp the tissue against the deck. Thereafter, staples removably stored in the cartridge body can be deployed into the tissue. The cartridge body includes staple cavities defined therein wherein staples are removably stored in the staple cavities. The staple cavities are arranged in six longitudinal rows. Three rows of staple cavities are positioned on a first side of a longitudinal slot and three rows of staple cavities are positioned on a second side of the longitudinal slot. Other arrangements of staple cavities and staples may be possible.

The staples are supported by staple drivers in the cartridge body. The drivers are movable between a first, or unfired position, and a second, or fired, position to eject the staples from the staple cavities. The drivers are retained in the cartridge body by a retainer which extends around the bottom of the cartridge body and includes resilient members configured to grip the cartridge body and hold the retainer to the cartridge body. The drivers are movable between their unfired positions and their fired positions by a sled. The sled is movable between a proximal position adjacent the proximal end and a distal position adjacent the distal end. The sled comprises a plurality of ramped surfaces configured to slide under the drivers and lift the drivers, and the staples supported thereon, toward the anvil.

Further to the above, in these surgical end effectors, the sled is moved distally by the firing member. The firing member is configured to contact the sled and push the sled toward the distal end. The longitudinal slot defined in the cartridge body is configured to receive the firing member. The anvil also includes a slot configured to receive the firing member. The firing member further comprises a first cam which engages the first jaw and a second cam which engages the second jaw. As the firing member is advanced distally, the first cam and the second cam can control the distance, or tissue gap, between the deck of the staple cartridge and the anvil. The firing member also comprises a knife configured to incise the tissue captured intermediate the staple cartridge and the anvil. It is desirable for the knife to be positioned at least partially proximal to the ramped surfaces such that the staples are ejected ahead of the knife.

Many surgical end effectors employ an axially movable firing beam that is attached to the firing member and is used to apply axial firing and retraction motions to the firing member. Many of such firing beams comprise a laminated construction that affords the firing beam with some degree of flexure about the articulation joint. As the firing beam traverses the articulation joint, the firing beam can apply de-articulation forces to the joint and can cause the beam to buckle. To prevent the firing beam from buckling under pressure, the articulation joint is commonly provided with lateral supports or “blow-out” plate features to support the portion of the beam that traverses the articulation joint. To advance the firing beam through an angle of greater than sixty degrees, for example, a lot of axial force is required. This axial force must be applied to the firing member in a balanced manner to avoid the firing member from binding with the jaws as the firing member moves distally. Any binding of the firing member with the jaws can lead to component damage and wear as well as require an increased amount of axial drive force to drive the firing member through the clamped tissue.

Other end effector designs employ a firing member that is rotary powered. In many of such designs, a rotary drive shaft extends through the articulation joint and interfaces with a rotatable firing member drive shaft that is rotatably supported within one of the jaws. The firing member threadably engages the rotatable firing member drive shaft and, as the rotatable firing member drive shaft is rotated, the firing member is driven through the end effector. Such arrangements require the supporting jaw to be larger to accommodate the firing member drive shaft. In such devices, a lower end of the firing member commonly operably interfaces with the drive shaft which can also result in an application of forces that tend to unbalance the firing member as it is driven distally.

FIGS. 1-4 illustrate one form of a surgical instrument 10 that may address many of the challenges facing surgical instruments with articulatable end effectors that are configured to cut and fasten tissue. In various embodiments, the surgical instrument 10 may comprise a handheld device. In other embodiments, the surgical instrument 10 may comprises an automated system sometimes referred to as a robotically-controlled system, for example. In various forms, the surgical instrument 10 comprises a surgical end effector 1000 that is operably coupled to an elongate shaft assembly 2000. The elongate shaft assembly 2000 may be operably attached to a housing 2002. In one embodiment, the housing 2002 may comprise a handle that is configured to be grasped, manipulated, and actuated by the clinician. In other embodiments, the housing 2002 may comprise a portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the surgical end effectors disclosed herein and their respective equivalents. In addition, various components may be “housed” or contained in the housing or various components may be “associated with” a housing. In such instances, the components may not be contained with the housing or supported directly by the housing. For example, the surgical instruments disclosed herein may be employed with various robotic systems, instruments, components and methods disclosed in U.S. Pat. No. 9,072,535, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, which is incorporated by reference herein in its entirety.

In one form, the surgical end effector 1000 comprises a first jaw 1100 and a second jaw 1200. In the illustrated arrangement, the first jaw 1100 comprises an elongate channel 1110 that comprises a proximal end 1112 and a distal end 1114 and is configured to operably support a surgical staple cartridge 1300 therein. The surgical staple cartridge 1300 comprises a cartridge body 1302 that has an elongate slot 1304 therein. A plurality of surgical staples or fasteners (not shown) are stored therein on drivers (not shown) that are arranged in rows on each side of the elongate slot 1304. The drivers are each associated with corresponding staple cavities 1308 that open through a cartridge deck surface 1306. The surgical staple cartridge 1300 may be replaced after the staples/fasteners have been discharged therefrom. Other embodiments are contemplated wherein the elongate channel 1110 and/or the entire surgical end effector 1000 may is discarded after the surgical staple cartridge 1300 has been used. Such end effector arrangements may be referred to as “disposable loading units”, for example.

In the illustrated arrangement, the second jaw 1200 comprises an anvil 1210 that comprises an elongate anvil body 1212 that comprises a proximal end 1214 and a distal end 1216. In one arrangement, a pair of stiffening rods or members 1213 may be supported in the anvil body 1212 to provide the anvil body 1212 with added stiffness and rigidity. The anvil body 1212 comprises a staple-forming undersurface 1218 that faces the first jaw 1100 and may include a series of staple-forming pockets (not shown) that corresponds to each of the staples or fasteners in the surgical staple cartridge 1300. The anvil body 1212 may further include a pair of downwardly extending tissue stop features 1220 that are formed adjacent the proximal end 1214 of the anvil body 1212. One tissue stop feature 1220 extends from each side of the anvil body 1212 such that a distal end 1222 on each tissue stop corresponds to the proximal-most staples/fasteners in the surgical staple cartridge 1300. When the anvil 1210 is moved to a closed position onto tissue positioned between the staple-forming undersurface 1218 of the anvil 1210 and the cartridge deck surface 1306 of the surgical staple cartridge 1300, the tissue contacts the distal ends 1222 of the tissue stop features 1220 to prevent the tissue from migrating proximally past the proximal-most staples/fasteners to thereby ensure that the tissue that is cut is also stapled. When the surgical staple cartridge is “fired” as will be discussed in further detail below, the staples/fasteners supported within each staple cavity are driven out of the staple cavity 1308 through the clamped tissue and into forming contact with the staple-forming undersurface 1218 of the anvil 1210.

As can be seen in FIGS. 5 and 6 , the proximal end 1214 of the anvil body 1212 comprises an anvil mounting portion 1230 that includes a pair of laterally extending mounting pins 1232 that are configured to be received in corresponding mounting cradles or pivot cradles 1120 formed in the proximal end 1112 of the elongate channel 1110. The mounting pins 1232 are pivotally retained within the mounting cradles 1120 by an anvil cap 1260 that may be attached to the proximal end 1112 of the elongate channel 1110 by mechanical snap features 1261 that are configured to engage retention formations 1113 on the elongate channel 1110. See FIG. 5 . In other arrangements, the anvil cap 1260 may be attached to the elongate channel 1110 by welding, adhesive, etc. Such arrangement facilitates pivotal travel of the anvil 1210 relative to the surgical staple cartridge 1300 mounted in the elongate channel 1110 about a pivot axis PA between an open position (FIG. 1 ) and a closed position (FIGS. 2-5 ). Such pivot axis PA may be referred to herein as being “fixed” in that the pivot axis does not translate or otherwise move as the anvil 1200 is pivoted from an open position to a closed position.

In the illustrated arrangement, the elongate shaft assembly 2000 defines a shaft axis SA and comprises a proximal shaft portion 2100 that may operably interface with a housing of the control portion (e.g., handheld unit, robotic tool driver, etc.) of the surgical instrument 10. The elongate shaft assembly 2000 further comprises an articulation joint 2200 that is attached to the proximal shaft portion 2100 and the surgical end effector 1000. In various instances, the proximal shaft portion 2100 comprises a hollow outer tube 2110 that may be operably coupled to a housing 2002. See FIG. 2 . As can be seen in FIG. 6 , the proximal shaft portion 2100 may further comprise a rigid proximal support shaft 2120 that is supported within the hollow outer tube 2110 and extends from the housing to the articulation joint 2200. The proximal support shaft 2120 may comprise a first half 2120A and a second half 2120B that may be coupled together by, for example, welding, adhesive, etc. The proximal support member 2120 comprises a proximal end 2122 and a distal end 2124 and includes an axial passage 2126 that extends therethrough from the proximal end 2122 to the distal end 2124.

As was discussed above, many surgical end effectors employ a firing member that is pushed distally through a surgical staple cartridge by an axially movable firing beam. The firing beam is commonly attached to the firing member in the center region of the firing member body. This attachment location can introduce an unbalance to the firing member as it is advanced through the end effector. Such unbalance can lead to undesirable friction between the firing member and the end effector jaws. The creation of this additional friction may require an application of a higher firing force to overcome such friction as well as can cause undesirable wear to portions of the jaws and/or the firing member. An application of higher firing forces to the firing beam may result in unwanted flexure in the firing beam as it traverses the articulation joint. Such additional flexure may cause the articulation joint to de-articulate—particularly when the surgical end effector is articulated at relatively high articulation angles. The surgical instrument 10 employs a firing system 2300 that may address many if not all of these issues as well as others.

As can be seen in FIGS. 5-11 , in at least one embodiment, the firing system 2300 comprises a firing member 2310 that includes a vertically-extending firing member body 2312 that comprises a top firing member feature 2320 and a bottom firing member feature 2350. A tissue cutting blade 2314 is attached to or formed in the vertically-extending firing member body 2312. See FIGS. 9 and 11 . In at least one arrangement, it is desirable for the firing member 2310 to pass through the anvil body 1212 with low friction, high strength and high stiffness. In the illustrated arrangement, the top firing member feature 2320 comprises a top tubular body 2322 that has a top axial passage 2324 extending therethrough. See FIG. 10 . The bottom firing member feature 2350 comprises a bottom tubular body 2352 that has a bottom axial passage 2354 extending therethrough. In at least one arrangement, the top firing member feature 2320 and the bottom firing member feature 2350 are integrally formed with the vertically-extending firing member body 2312. As can be seen in FIG. 12 , the anvil body 1212 comprises an axially extending anvil slot 1240 that has a cross-sectional shape that resembles a “keyhole”. Similarly, the elongate channel 1110 comprises an axially extending channel slot 1140 that also has a keyhole cross-sectional shape.

Traditional firing member arrangements employ long flexible cantilever wings that extend from a top portion and a bottom portion of the firing member. These cantilever wings slidably pass through slots in the anvil and channel that are commonly cut with a rectangular t-cutter which tended to produce higher friction surfaces. Such long cantilever wings have minimum surface area contact with the anvil and channel and can result in galling of those components. The keyhole-shaped channel slot 1140 and keyhole-shaped anvil slot 1240 may be cut with a round t-cutter and may be finished with a reamer/borer which will result in the creation of a lower friction surface. In addition, the top tubular body 2322 and the bottom tubular body 2352 tend to be stiffer than the prior cantilever wing arrangements and have increased surface area contact with the anvil and channel, respectively which can reduce galling and lead to a stronger sliding connection. Stated another way, because the anvil slot 1240 and the channel slot 1140 are keyhole-shaped and have less material removed than a traditional rectangular slot, the geometry and increased material may result in a stiffer anvil and channel when compared to prior arrangements.

Turning to FIGS. 9-11 , in one arrangement, the firing system 2300 further comprises an upper flexible spine assembly 2400 that is operably coupled to the top firing member feature 2320 and a lower flexible spine assembly 2500 that is operably coupled to the bottom firing member feature 2350. In at least one embodiment, the upper flexible spine assembly 2400 comprises an upper series 2410 of upper vertebra members 2420 that are loosely coupled together by an upper flexible coupler member 2402 that is attached to the top firing member feature 2320. The upper flexible coupler member 2402 may comprises a top cable 2404 that extends through the top axial passage 2324 in the top firing member feature 2320 and a distal end 2406 of the top cable 2404 is attached to a retainer ferrule 2408 that is secured with the top axial passage 2324.

As can be seen in FIG. 13 , each upper vertebra member 2420 comprises an upper vertebra body portion 2422 that has a proximal end 2424 and a distal end 2428. An upper hollow passage 2429 extends through the upper vertebra body portion 2422 to accommodate passage of the upper flexible coupler member 2402 therethrough. Each upper vertebra member 2420 further comprises a downwardly extending upper drive feature or upper vertebra member tooth 2450 that protrudes from the upper vertebra body portion 2422. Each upper vertebra member tooth 2450 has a helix-shaped proximal upper face portion 2452 and a helix-shaped distal upper face portion 2454. Each proximal end 2424 of the upper vertebra body portions 2422 has an upper proximal mating feature 2426 therein and each distal end 2428 has an upper distal mating feature 2430 formed therein. In at least one embodiment, the upper proximal mating feature 2426 comprises a concave recess 2427 and each upper distal mating feature 2430 comprises a convex mound 2431. When arranged in the upper series 2410, the convex mound 2431 on one upper vertebra member 2420 contacts and mates with the concave recess 2427 on an adjacent upper vertebra member 2420 in the upper series 2410 to maintain the upper vertebra members 2420 roughly in alignment so that the helix-shaped proximal upper face portion 2452 and a helix-shaped distal upper face portion 2454 on each respective upper tooth 2450 can be drivingly engaged by a rotary drive screw 2700 as will be discussed in further detail below.

Similarly, in at least one embodiment, the lower flexible spine assembly 2500 comprises a lower series 2510 of lower vertebra members 2520 that are loosely coupled together by a lower flexible coupler member 2502 that is attached to the bottom firing member feature 2350. The lower flexible coupler member 2502 may comprises a lower cable 2504 that extends through the bottom axial passage 2354 in the bottom firing member feature 2350 and a distal end 2506 of the bottom cable 2504 is attached to a retainer ferrule 2508 that is secured with the bottom axial passage 2354.

As can be seen in FIG. 14 , each lower vertebra member 2520 comprises a lower vertebra body portion 2522 that has a proximal end 2524 and a distal end 2528. A lower hollow passage 2529 extends through the lower vertebra body portion 2522 to accommodate passage of the lower flexible coupler member 2502 therethrough. Each lower vertebra member 2520 further comprises an upwardly extending lower drive feature or lower vertebra member tooth 2550 that protrudes upward from the lower vertebra body portion 2522. Each lower vertebra member tooth 2550 has a helix-shaped proximal lower face portion 2552 and a helix-shaped distal lower face portion 2554. Each proximal end 2524 of the lower vertebra body portions 2522 has a lower proximal mating feature 2526 therein and each distal end 2528 has a lower distal mating feature 2530 formed therein. In at least one embodiment, the lower proximal mating feature 2526 comprises a concave recess 2527 and each lower distal mating feature 2530 comprises a convex mound 2531. When arranged in the lower series 2510, the convex mound 2531 on one lower vertebra member 2520 contacts and mates with the concave recess 2527 on an adjacent lower vertebra member 2520 in the lower series 2510 to maintain the lower vertebra members 2520 roughly in alignment so that the helix-shaped proximal lower face portion 2552 and a helix-shaped distal lower face portion 2554 on each respective lower vertebra member tooth 2550 can be drivingly engaged by a rotary drive screw 2700 as will be discussed in further detail below.

Now turning to FIGS. 5, 7, and 8 , in at least one arrangement, the firing drive system 2300 further comprises a rotary drive screw 2700 that is configured to drivingly interface with the upper series 2410 of upper vertebra members 2420 and the lower series 2510 of lower vertebra members 2520. In the illustrated arrangement, the rotary drive screw 2700 is driven by a rotary drive system 2600 that comprises a proximal rotary drive shaft 2610 that is rotatably supported within the axial passage 2126 within the proximal support shaft 2120. See FIG. 7 . The proximal rotary drive shaft 2610 comprises a proximal end 2612 and a distal end 2614. The proximal end 2612 may interface with a gear box 2004 or other arrangement that is driven by a motor 2006 or other source of rotary motion housed in the housing of the surgical instrument. See FIG. 2 . Such source of rotary motion causes the proximal rotary drive shaft to rotate about the shaft axis SA within the axial passage 2126 in the proximal support shaft 2120.

The proximal rotary drive shaft 2610 is operably supported within the elongate shaft assembly 2000 in a location that is proximal to the articulation joint 2200 and operably interfaces with a constant velocity (CV) drive shaft assembly 2620 that “spans” or extends axially through the articulation joint 2200. As can be seen in FIGS. 8, 16, and 17 , in at least one arrangement, the CV drive shaft assembly 2620 comprises a proximal CV drive assembly 2630 and a distal CV drive shaft 2670. The proximal CV drive assembly 2630 comprises a proximal shaft segment 2632 that consists of an attachment shaft 2634 that is configured to be non-rotatably received within a similarly-shaped coupler cavity 2616 in the distal end 2614 of the proximal rotary drive shaft 2610. The proximal shaft segment 2632 operably interfaces with a series 2640 of movably coupled drive joints 2650.

As can be seen in FIG. 18 , in at least one arrangement, each drive joint 2650 comprises a first or distal sphere portion 2660 and a second or proximal sphere portion 2652. The distal sphere portion 2660 is larger than the proximal sphere portion 2652. The distal sphere portion 2660 comprises a socket cavity 2662 that is configured to rotatably receive a proximal sphere portion 2652 of an adjacent drive joint 2650 therein. Each proximal sphere portion 2652 comprises a pair of diametrically opposed joint pins 2654 that are configured to be movably received in corresponding pin slots 2664 in the distal sphere portion 2660 of an adjacent drive joint 2650 as can be seen in FIG. 16 . A proximal sphere portion 2652P of a proximal-most drive joint 2650P is rotatably received in a distal socket portion 2636 of the proximal shaft segment 2632 as shown in FIG. 16 . The joint pins 2654P are received within corresponding pin slots 2637 in the distal socket portion 2636. As can be further seen in FIG. 16 , a distal-most drive joint 2650D in the series 2640 of movably coupled drive joints 2650 is movably coupled to a distal CV drive shaft 2670.

In at least one arrangement, the distal CV drive shaft 2670 comprises a proximal sphere portion 2672 that is sized to be movably received in the socket cavity 2662D in the distal-most drive joint 2650D. The proximal sphere portion 2672 includes joint pins 2674 that are movably received in the pin slots 2664D in the distal-most drive joint 2650D. The distal CV drive shaft 2670 further comprises a distally extending shaft stem 2676 that is configured to be non-rotatably coupled to the rotary drive screw 2700 that is positioned distal to the articulation joint 2200. The distal CV drive shaft 2670 includes a flange 2677 and a mounting barrel portion 2678 for receiving a thrust bearing housing 2680 thereon.

In the illustrated arrangement, when the series 2640 of movably coupled drive joints 2650 articulates, the joint pins 2674 remain in the corresponding pin slots 2664 of an adjacent drive joint 2650. In the example illustrated in FIG. 18 , each drive joint may be capable of approximately eighteen degrees of articulation in the pitch and yaw directions. FIG. 16 illustrates an angle of the series of 2640 of drive joints 2650 when each drive joint 2650 in the series are fully articulated ninety degrees in pitch and yaw which yields an angle α of approximately 100.9 degrees. In such arrangement, the outer surface of each distal sphere portion 2660 clears the outer surface of the adjacent or adjoining proximal sphere portion 2652 allowing for unrestricted motion until the eighteen degree limit is reached. The rigid design and limited small angles allow the series 2640 of movably coupled drive joints 2650 to carry high loads torsionally at an overall large angle.

In the illustrated arrangement, the articulation joint 2200 comprises an articulation joint spring 2230 that is supported within an outer elastomeric joint assembly 2210. The outer elastomeric joint assembly 2210 comprises a distal end 2212 that is attached to the proximal end 1112 of the elongate channel 1110. For example, as can be seen in FIG. 6 , the distal end 2212 of the outer elastomeric joint assembly 2210 is attached to the proximal end 1112 of the elongate channel 1110 by a pair of cap screws 2722 that extend through a distal mounting bushing 2720 to be threadably received in the proximal end 1112 of the elongate channel 1110. A proximal end 2214 of the elastomeric joint assembly 2210 is attached to the distal end 2124 of the proximal support shaft 2120. The proximal end 2214 of the elastomeric joint assembly 2210 is attached to the distal end 2124 of the proximal support member 2120 by a pair of cap screws 2732 that extend through a proximal mounting bushing 2750 to be threadably received in threaded inserts 2125 mounted within the distal end 2124 of the proximal support shaft 2120.

To prevent the drive joints 2650 from buckling during articulation, the series 2640 of movably coupled drive joints 2650 extend through at least one low friction articulation joint spring 2730 that is supported within the outer elastomeric joint assembly 2210. See FIG. 19 . The articulation joint spring 2730 is sized relative to the drive joints 2650 such that a slight radial clearance is provided between the articulation joint spring 2730 and the drive joints 2650. The articulation joint spring 2730 is designed to carry articulation loads axially which may be significantly lower than the torsional firing loads. The joint spring(s) is longer than the series 2640 of drive joints 2650 such that the drive joints are axially loose. If the “hard stack” of the series 2640 of drive joints 2650 is longer than the articulation joint spring(s) 2730 hard stack, then the drive joints 2650 may serve as an articulation compression limiter causing firing loads and articulation loads to resolve axially through the series 2640 of the drive joints 2650. When the firing loads resolve axially through the series 2640 of the drive joints 2650, the loads may try to straighten the articulation joint 2200 or in other words cause de-articulation. If the hard stack of the articulation joint spring(s) 2730 is longer than the hard stack of the series 2640 of the drive joints 2650, the firing loads will then be contained within the end effector and no firing loads will resolve through the drive joints 2650 or through the springs(s) 2730.

To further ensure that the drive joints 2650 are always engaged with each other, a proximal drive spring 2740 is employed to apply an axial biasing force to the series 2640 of drive joints 2650. For example, as can be seen in FIGS. 8, 19, and 20 , the proximal drive spring 2740 is positioned between the proximal mounting bushing 2734 and a support flange that is formed between the distal socket portion 2636 and a proximal barrel portion 2638 of the proximal shaft segment 2632. In one arrangement, the proximal drive spring 2740 may comprise an elastomeric O-ring/bushing received on the proximal barrel portion 2638 of the proximal shaft segment 2632. The proximal drive spring 2740 lightly biases the drive joints 2650 together to decrease any gaps that may occur during articulation. This ensures that the drive joints 2650 transfer loads torsionally. It will be appreciated, however, that in at least one arrangement, the proximal drive spring 2740 does not apply a high enough axial load to cause firing loads to translate through the articulation joint 2200.

As can be seen in FIGS. 9 and 10 , the top firing member feature 2320 on the firing member 2310 comprises a distal upper firing member tooth segment 2330 that is equivalent to one half of an upper tooth 2450 on each upper vertebra member 2420. In addition, a proximal upper firing member tooth 2336 that is identical to an upper tooth 2450 on each upper vertebra member 2420 is spaced from the distal upper firing member tooth segment 2330. The distal upper firing member tooth segment 2330 and the proximal upper firing member tooth 2336 may be integrally formed with the top firing member feature 2320 of the firing member 2310. Likewise, the bottom firing member feature 2350 of the firing member 2310 comprises a distal lower firing member tooth 2360 and a proximal lower firing member tooth 2366 that are integrally formed on the bottom firing member feature 2350. For example, in at least one arrangement, the firing member 2310 with the rigidly attached teeth 2330, 2336, 2360, and 2366 may be fabricated at one time as one unitary component using conventional metal injection molding techniques.

As indicated above, each of the upper vertebra members 2520 is movably received on an upper flexible coupler member 2402 in the form of a top cable 2404. As was described above, the distal end 2406 of the top cable 2404 is secured to the top firing member feature 2320 of the firing member 2310. Similarly, each of the lower vertebra members 2520 is movably received on a lower flexible coupler member 2502 in the form of a lower cable 2504. A distal end 2506 of the lower cable 2504 is secured to the bottom firing member feature 2350 of the firing member 2310. In at least one arrangement, the top cable 2404 and the bottom cable 2504 extend through the proximal shaft portion 2100 and, as will be discussed in further detail below, may interface with a bailout arrangement supported in the housing for retracting the firing member 2310 back to its home or starting position should the firing member drive system fail.

Turning again to FIG. 8 , the axial length AL_(u) of the upper series 2410 of upper vertebra members 2420 and the axial length AL_(l) of the lower series 2510 of lower vertebra members 2520 are equal and must be sufficiently long enough to facilitate the complete distal advancement of the firing member 2310 from the home or starting position to a distal-most ending position within the staple cartridge while the proximal-most upper vertebra members 2420 in the upper series 2410 of upper vertebra members 2420 and the proximal-most lower vertebra members 2520 in the lower series 2510 of lower vertebra members 2520 remain in driving engagement with the rotary drive screw 2700. As can be seen in FIG. 8 , an upper compression limiting spring 2421 is configured to interface with a proximal-most upper vertebra member 2420P in the upper series 2410 of upper vertebra members 2420. The upper compression limiting spring 2421 is journaled on the top cable 2404 and is retained in biasing engagement with the proximal-most upper vertebra member 2420P by an upper spring holder 2423 that is retained in position by an upper ferrule 2425 that is crimped onto the top cable 2404. The top cable 2404 extends through an upper hypotube 2433 that is supported in the proximal support shaft. Likewise, a lower compression limiting spring 2521 is configured to interface with a proximal-most, lower vertebra member 2520P in the lower series 2510 of lower vertebra members 2520. The lower compression spring 2521 is journaled on the lower cable 2504 and is retained in biasing engagement with the proximal-most, lower vertebra member 2520P by a lower spring holder 2523 that is retained in position by a lower ferrule 2525 that is crimped onto the lower cable 2504. The lower cable 2504 extends through a lower hypotube 2533 that is supported in the proximal support shaft.

When the upper vertebra members 2420 and the lower vertebra members 2520 angle through the articulation joint (after the end effector has been positioned in an articulated position), the gaps between the respective vertebra members 2420, 2520 increase in each series 2410, 2510 which causes the springs 2421, 2521 to become tighter. The compression limiting springs 2421, 2521 provide enough slack in the cables 2404, 2504, respectively to enable the vertebra members 2420, 2520 angle through the most extreme articulation angles. If the cables 2404, 2504 are pulled too tight, the spring holders 2423, 2523 will contact their respective proximal-most vertebra members 2420P, 2520P. Such compression limiting arrangements ensure that the vertebra members 2420, 2520 in their respective series 2410, 2510 always remain close enough together so that the rotary drive screw 2700 will always drivingly engage them in the manner discussed in further detail below. When the vertebra members 2420, 2520 are aligned straight again, the compression limiting springs 2421, 2521 may partially relax while still maintaining some compression between the vertebra members.

As indicated above, when the upper vertebra members 2420 are arranged in the upper series 2410 and lower vertebra members 2520 are arranged in the lower series 2510, the convex mounds and concave recesses in each vertebra member as well as the compression limiter springs serve to maintain the upper and lower vertebra members in relatively linear alignment for driving engagement by the rotary drive screw 2700. As can be seen in FIGS. 9 and 10 , when the upper vertebra members 2420 are in linear alignment, the upper teeth 2450 are spaced from each other by an opening space generally designated as 2460 that facilitates driving engagement with the helical drive thread 2170 on the rotary drive screw. Similarly, when the lower vertebra members 2520 are in linear alignment, the lower vertebra member teeth 2550 are spaced from each other by an opening space generally designated as 2560 that facilitates driving engagement with the helical drive thread 2170 of the rotary drive screw 2700.

Turning to FIGS. 8 and 22 , the rotary drive screw 2700 comprises a screw body 2702 that has a socket 2704 therein for receiving the distally extending shaft stem 2676 of the distal CV drive shaft 2670. An internal radial groove 2714 (FIG. 10 ) is formed in the screw body 2702 for supporting a plurality of ball bearings 2716 therein. In one arrangement, for example, 12 ball bearings 2716 are employed. The radial groove 2714 supports the ball bearings 2716 between the screw body 2702 and a distal end of the thrust bearing housing 2680. The ball bearings 2716 serve to distribute the axial load of the rotary drive screw 2700 and significantly reduce friction through the balls' rolling motion.

As can be seen in FIG. 23 , a helical drive thread 2710 is provided around the screw body 2702 and serves to form a proximal thread scoop feature 2712. The proximal thread scoop feature 2712 is formed with a first pitch 2713 and the remaining portion of the helical drive thread 2710 is formed with a second pitch 2715 that differs from the first pitch 2713. In FIGS. 22 and 23 , area 2718 illustrates where the first pitch 2713 and the second pitch 2715 converge. In at least one embodiment, the first pitch 2713 is larger than the second pitch 2715 to ensure that the rotary drive screw 2700 captures and “scoops up” or drivingly engages every upper vertebra member 2420 and every lower vertebra member 2520. As can be seen in FIG. 24 , a proximal end 2717 of the helical drive thread 2710 that has the first pitch 2713 has scooped into the into the opening space 2560 between two adjacent lower vertebra member teeth 2550A and 2550B while the center portion 2719 of the helical drive thread 2710 that has the second pitch 2715 is in driving engagement with the helix-shaped distal lower face portion 2554 on the lower vertebra member tooth 2550B and the helix-shaped proximal lower face portion 2552 on the proximal lower firing member tooth 2366. As can also be appreciated, the scoop feature 2712 may not contact the helix-shaped distal lower face portion 2554A of the lower vertebra member tooth 2550A as it scoops up the lower vertebra member tooth 2550B when driving the firing member 2310 distally. The helical drive thread 2710 interacts with the teeth 2450 of the upper vertebra members 2420 in a similar manner.

A power screw is a threaded rod with a full three hundred sixty degree nut around it. Rotation of the power screw causes the nut to advance or move longitudinally. In the present arrangements, however, due to space constraints, a full three hundred sixty degree nut cannot fit inside the end effector. In a general sense, the upper flexible spine assembly 2400 and the lower flexible spine assembly 2500 comprise a radially/longitudinally segmented “power screw nut” that is rotatably driven by the rotary drive screw 2700. When the rotary drive screw is rotated in a first rotary direction, the rotary drive screw 2700 drives one or more vertebra members in each of the upper series and lower series of vertebra members longitudinally while the vertebra members 2420, 2520 stay in the same locations radially. The upper series 2410 and lower series 2510 are constrained from rotating around the rotary drive screw 2700 and can only move longitudinally. In one arrangement, the upper vertebra members 2420 in the upper series 2410 and the lower vertebra members 2520 in the lower series 2510 only surround the rotary drive screw 2700 with less than ten degrees each.

FIG. 25 illustrates the firing member 2310 in the home or starting position. As can be seen in FIG. 25 , a portion of the helical drive thread 2710 on the rotary drive screw 2700 is engaged between the distal upper firing member tooth segment 2330 and the proximal upper firing member tooth 2336 and another portion of the helical drive thread 2710 is engaged between the distal lower firing member tooth 2360 and a proximal lower firing member tooth 2366 on the firing member 2310. Such arrangement enables the rotary drive screw 2700 to precisely control the distal and proximal movement of the firing member 2310 which, as will be discussed in further detail below, can result in the precise movement of the anvil 1210. Once the firing member 2310 has been sufficiently distally advanced during a firing stroke, the helical drive thread 2710 operably engages the teeth on the upper and lower vertebras. See FIG. 26 .

The surgical instrument 10 also comprises an articulation system 2240 that is configured to apply articulation motions to the surgical end effector 1000 to articulate the surgical end effector relative to the elongate shaft assembly 2000. In at least one arrangement, for example, the articulation system comprises four articulation cables 2242, 2246, 2250, and 2254 that extend through the elongate shaft assembly 2000. See FIG. 27 . In the illustrated arrangement, the articulation cables 2242, 2246 pass through the proximal mounting bushing 2750, the proximal end 2214 of the elastomeric joint assembly 2210, as well as a central rib segment 2216 to be secured to the distal end 2212 of the elastomeric joint assembly 2210 or other portion of the surgical instrument. Likewise, the articulation cables 2250 and 2254 extend through the proximal mounting bushing 2750, the proximal end 2214 of the elastomeric joint assembly 2210, as well as a central rib segment 2218 to be secured to the distal end 2212 of the elastomeric joint assembly 2210 or other portion of the surgical end effector. The cables 2242, 2246, 2250, and 2254 operably interface with an articulation control system that is supported in the housing of the surgical instrument 10. For example, a proximal portion of each cable 2242, 2246, 2250, and 2254 may be spooled on a corresponding rotary spool or cable-management system 2007 (FIG. 2 ) in the housing portion of the surgical instrument 10 that is configured to payout and retract each cable 2242, 2246, 2250, and 2254 in desired manners. The spools/cable management system may be motor powered or manually powered (ratchet arrangement, etc.). FIG. 29 illustrates articulation of the surgical end effector 1000 through a first articulation plane relative to the elongate shaft assembly 2000. FIG. 30 illustrates articulation of the surgical end effector 1000 through a second articulation plane relative to the elongate shaft assembly 2000. FIG. 31 illustrates articulation of the surgical end effector 1000 through multiple articulation planes relative to the elongate shaft assembly 2000.

FIGS. 32-34 illustrate an alternative articulation joint 2200′ in the form of an elastomeric joint assembly 2210′. As can be seen in FIG. 33 , each articulation cable passes through a corresponding spring 2215′ that is mounted in the ribs 2216′ of the elastomeric joint assembly 2210′. For example, cable 2242 extends through spring 2244. Cable 2246 extends through spring 2248. Cable 2250 extends through spring 2252 and cable 2254 extends through spring 2256. As indicated above, the end effector is articulated by pulling on and relaxing the appropriate cables 2242, 2246, 2250 and 2254. To achieve higher articulation angles with greater joint stability, each of the springs 2244, 2248, 2252, and 2256 can slide through the ribs of the elastomeric joint to push the end effector and pull on the cables extending therethrough. The springs 2244, 2248, 2252, and 2256 will also retract into the ribs when the cables 2242, 2246, 2250, and 2254 are pulled tight. Each of the springs 2244, 2248, 2252, and 2256 loosely seat over the particular cable that passes therethrough. Each cable and corresponding spring may terminate or otherwise be coupled to a corresponding solid rod that is supported in the elongate shaft assembly 2000 and may be pushed and pulled from its proximal end. When the cable is pulled, the corresponding spring would carry little to no load. When the spring is pushed, the cable would carry little load, but will help limit the end effector movement. This interaction between the cable and spring may facilitate higher articulation angles that may approach ninety degrees, for example.

Because the radially/longitudinally segmented power screw nut arrangement disclosed herein does not have the same constraints as a three hundred sixty degree nut, the upper vertebra members 2420 in the upper series 2410 and the lower vertebra members 2520 in the lower series 2510 are constrained to ensure that their loads are transferred to the firing member in a longitudinal direction. To maintain each of the upper vertebra members 2420 in the desired orientation and to prevent the upper vertebra members 2420 from becoming snagged or disoriented when traversing through the articulation joint 2200, the upper vertebra members 2420 are aligned to pass through an upper sleeve 2470 that extends through an upper portion of the outer elastomeric joint assembly 2210 of the articulation joint 2200. See FIGS. 27, 28, and 35 . A distal end 2472 of the upper sleeve 2470 is supported in the proximal end 1112 of the elongate channel 1110 and a proximal end 2474 of the upper sleeve 2470 is supported in the distal end of the proximal support shaft 2120. The upper sleeve 2470 is fabricated from a polymer or plastic material that has a low coefficient of friction and is flexible to enable the upper sleeve 2470 to flex with the outer elastomeric joint assembly 2210. The upper sleeve 2470 protects the upper vertebra members 2420 from contacting the outer elastomeric joint assembly 2210 that is fabricated from an elastomeric material that may have a higher coefficient of friction than the coefficient of friction of the material of the upper sleeve 2470. Stated another way, the upper sleeve 2470 forms a low friction, flexible, continuous, uninterrupted, and fully encapsulating path for the upper vertebra members 2420 as they traverse the articulation joint 2200.

Similarly, a lower sleeve 2570 is employed to support the lower vertebra members 2520 as they pass through the articulation joint 2200. A distal end 2572 of the lower sleeve 2570 is supported in the proximal end of the elongate channel and a proximal end of the lower sleeve 2570 is supported in the distal end of the proximal support shaft 2120. Like the upper sleeve 2470, the lower sleeve 2570 is fabricated from a polymer or plastic material that has a low coefficient of friction and is flexible to enable the lower sleeve 2570 to flex with the outer elastomeric joint assembly 2210. The lower sleeve 2570 protects the lower vertebra members 2520 from contacting the outer elastomeric joint assembly 2210 as they pass through the articulation joint 2200. Stated another way, the lower sleeve 2570 forms a low friction, flexible, continuous, uninterrupted, and fully encapsulating path for the lower vertebra members 2520 as they traverse the articulation joint 2200. In various embodiments, the upper sleeve 2470 and the lower sleeve 2570 are configured to bend freely without creating a kink. To prevent the formation of kinks in the sleeves, in at least one arrangement, the sleeves 2470, 2570 are supported within the outer elastomeric joint assembly 2210 such that the sleeves may move axially. For example, when the articulation joint angles up, the lower sleeve 2570 may slide distally and have a large bend radius; the upper sleeve 2470 in the same example, may slide proximally and have a tighter bend radius. By moving axially, the amount of material exposed outside of the joint assembly 2210 which might otherwise be susceptible to kinking under a tight bend radius is reduced. In at least one arrangement, the distal end 2472 of the upper sleeve 2470 is formed with an upper scoop 2476 that is configured to funnel the upper vertebra members 2420 into the anvil cap 1260. Similarly, the distal end of the lower sleeve 2570 may be formed with a lower scoop that is configured to funnel the lower vertebra members 2520 into the channel slot 1140 in the elongate channel 1110.

As indicated above, the anvil mounting portion 1230 comprises a pair of laterally extending mounting pins 1232 that are configured to be received in corresponding mounting cradles or pivot cradles 1120 that are formed in the proximal end 1112 of the elongate channel 1110. The mounting pins 1232 are pivotally retained within the mounting cradles 1120 by an anvil cap 1260 that is attached to the proximal end 1112 of the elongate channel 1110 in the above-described manners. The anvil cap 1260 comprises a proximal end 1262 and a distal end 1264 and has a keyhole-shaped vertebra passage 1266 extending therethrough to accommodate passage of the top firing member feature 2320 and upper vertebra members 2420 therethrough. FIG. 36 illustrates the vertebra passage 1266 in the anvil cap 1260. When the rotary drive screw 2700 applies load to the upper vertebra members 2420, the vertebra members 2420 will tend to tilt about the area A in FIG. 37 , so the upper vertebra member tooth 2450 is no longer square with the rotary drive screw 2700 and may instead experience a higher-pressure line contact. Areas B in FIG. 37 show where the upper vertebra member 2420 stops tilting. To ensure that most of the loads stay in the longitudinal direction to perform useful work, the upper vertebra member tooth 2450 must be angled the same amount as the upper vertebra member 2420 tilts. Thus, when the upper vertebra member 2420 tilts, the upper vertebra member tooth 2450 will still maintain surface contact with the helical drive member 2710 on the rotary drive screw 2700 and all loads will be directed longitudinally and not vertically. The slightly angled upper vertebra member tooth 2450 may behave like a square thread when the vertebra member 2420 is tilted and better distributes loads to lower the pressure contact. By directing most of the loads in the longitudinal direction, vertical loads are avoided which could result in the establishment of friction that would counter the longitudinal loads. The upper vertebra members 2420 react similarly as they pass down the keyhole-shaped anvil slot 1240. Likewise, the lower vertebra members 2520 react similarly as they pass through the keyhole-shaped axially extending channel slot 1140 in the elongate channel 1110.

In the illustrated arrangement, the anvil 1210 is moved to the open position by a pair of anvil springs 1270 that are supported within the proximal end of the elongate channel. See FIGS. 38, 42, and 43 . The springs 1270 are positioned to apply a pivotal biasing force to corresponding anvil control arms 1234 that may be integrally formed with anvil mounting portion 1230 and extend downwardly therefrom. See FIG. 38 .

FIGS. 39-41 illustrate portions of the anvil 1210, the firing member 2310, and the anvil cap 1260 when the anvil 1210 is open (FIG. 39 ), when the anvil 1210 is partially closed (FIG. 40 ) and after the firing member has been advanced distally from the home or starting position (FIG. 41 ). As can be seen in FIG. 39 , when the firing member 2310 is in the home or starting position, the top firing member feature 2320 is completely received within the vertebra passage 1266 in the anvil cap 1260. During a firing stroke, the top firing member feature 2320 and the upper vertebra members 2420 in the upper series 2410 must transition from the vertebra passage 1266 in the anvil cap 1260 to the keyhole-shaped anvil slot 1240. Thus, it is desirable to minimize any gap “G” between the anvil mounting portion 1230 and a distal end 1264 of the anvil cap 1260. To minimize this gap G while facilitate unimpeded pivotal travel of the anvil 1210, the distal end 1264 of the anvil cap 1260 is formed with a curved cap surface 1265 that matches a curved mating surface 1231 on the anvil mounting portion 1230. Both surfaces 1265, 1231 are curved and concentric about the pivot axis PA or some other point. Such arrangement allows the anvil 1210 to move radially and not interfere with the anvil cap 1260 while maintaining a minimal gap G therebetween. The gap G between the anvil mounting portion 1230 and the distal end 1264 of the anvil cap 1260 is significantly shorter than a length of an upper vertebra member 2420 which facilitates easy transition of each upper vertebra member 2420 from the vertebra passage 1266 in the anvil cap 1260 to the keyhole-shaped anvil slot 1240. In addition, to further assist with the transition of the top firing member feature 2320 into the keyhole-shaped anvil slot 1240, a ramped surface 1241 is formed adjacent the curved mating surface 1231 on the anvil mounting portion 1230. As the firing member 2310 is initially advanced distally from the home or starting position, a distal end of the top firing member feature 2320 contacts the ramped surface 1241 and begins to apply a closing motion to the anvil 1210 as can be seen in FIG. 40 . Further distal advancement of the firing member 2310 during the firing stroke or firing sequence causes the top firing member feature to enter the keyhole shaped anvil slot 1240 to completely close the anvil 1210 and retain the anvil 1210 in the closed position during the firing sequence. See FIG. 41 .

In general, the highest firing forces established in an endocutter are associated with cutting and stapling tissue. If those same forces can be used to close the anvil, then the forces generated during pre-clamping and grasping of tissue can be high as well. In at least one arrangement, the firing member body 2312 further comprises a firing member wing or tab 2355 that extends laterally from each lateral side of the firing member body 2312. See FIGS. 15 and 36 . The firing member wings 2355 are positioned to contact the corresponding anvil control arms 1234 when the firing member 2310 is driven in the proximal direction PD from the home or starting position to quickly close the anvil 1210 for grasping purposes. In at least one arrangement, when the firing member 2310 is in the home or starting position, the firing member wings 2355 are located distal to the anvil control arms 1234 as shown in FIG. 42 . When the firing member 3210 is moved proximally, the firing member wings 2355 push the anvil control arms 1234 (pivotal direction C) against the bias of the anvil springs 1270. See FIG. 42 . In one arrangement, the firing member 2310 only has to move a short distance D to pivot the anvil 1210 to a closed position. In one embodiment, distance D may be approximately 0.070 inches long, for example. This short movement allows for a quick response. Because the anvil pivot point or pivot axis PA is relatively far from the firing member wings 2355 which creates a substantial moment arm, the proximal movement of the firing member 2310 (and firing member wings 2355) results in an application of high pre-compression torque to the anvil 1210 to move the anvil 1210 to a closed position. Thus, the firing member wings 2355 may be referred to herein as “pre-compression features”. See FIG. 43 . Thus, the clinician may use the surgical end effector 1000 to grasp and manipulate tissue between the anvil 1210 and the surgical staple cartridge 1300 without cutting the tissue and forming the staples, by advancing the firing member 2310 proximally the short distance D to cause the anvil 1210 to quickly pivot to a closed position.

The firing member 2310 may be moved in the proximal direction PD by rotating the rotary drive screw 2700 in a second rotary direction. Thus, when the firing member 2310 is in the “home” or starting position, the anvil 1210 may be biased into the fully open position by the anvil springs 1270. Activation of the rotary drive system 2600 to apply a rotary motion to the rotary drive screw 2700 in a first rotary direction will cause the firing member 2310 to be advanced distally from the home or starting position to apply an anvil closure motion to the anvil 1210 to move the anvil closed to clamp the target tissue between the anvil 1210 and the surgical staple cartridge 1300. Continued rotation of the rotary drive screw in the first rotary direction will cause the firing member 2310 to continue to distally advance through the surgical end effector 1000. As the firing member 2310 moves distally, the firing member 2310 contacts a sled 1312 (FIG. 19 ) that is supported in the surgical staple cartridge 1300 and drives the sled 1312 distally through the staple cartridge body 1302. When the firing member 2310 is in the home or starting position, the surgeon may wish to use the surgical end effector to grasp and manipulate tissue. To do so, the rotary drive system is actuated to apply a second rotary drive motion to the rotary drive screw 2700 in a second rotary direction that is opposite to the first rotary direction. Such rotary movement of the rotary drive screw 2700 in the second rotary direction will drive the firing member 2310 proximally from the starting position and cause the anvil 1210 to quickly pivot to the closed position. Thus, in accordance with at least one embodiment, the “home or starting position” of the firing member 2310 is not its proximal-most position.

If during the firing process, the rotary drive system 2600 quits rotating, the firing member 2310 may become stuck within the surgical end effector. In such instance, the top firing member feature 2320 may remain engaged with the anvil 1210 and the bottom firing member feature 2350 may remain engaged with the elongate channel 1110 and thereby prevent the surgeon from moving the anvil 1210 to an open position to release the tissue clamped between anvil 1210 and surgical staple cartridge 1300. This could occur, for example, if the motor or other control arrangement supplying the rotary drive motions to the rotary drive shaft 2610 fails or otherwise becomes inoperative. In such instances, the firing member 2310 may be retracted back to the home or starting position within the surgical end effector 1000 by pulling the top cable 2404 and the lower cable 2504 in a proximal direction. For example, a proximal portion of the top cable 2404 and a proximal portion of the lower cable 2505 may be spooled on a rotary spool or cable-management system 2009 (FIG. 2 ) in the housing portion of the surgical instrument 10 that is configured to payout the top cable 2404 and lower cable 2504 during the firing stroke and also retract the cables 2404, 2504 in a proximal direction should the firing member 2310 need to be retracted. The cable management system 2009 may be motor powered or manually powered (ratchet arrangement, etc.) to apply retraction motions to the cables 2404, 2504. When the cables 2404, 2504 are retracted, the upper vertebra members 2420 and lower vertebra members 2520 will cause the rotary drive screw 2700 to spin in reverse.

The following equation may be used to determine whether the rotary drive screw 2700 will spin in reverse depending upon the lead (L), pitch diameter (d_(p)), tooth angle (α) and friction (μ):

$\mu \geq {\frac{L}{\pi d_{p}}\cos\;\alpha}$

The rotary drive screw 2700 may self-lock if the above equation is true. For the most part, in many instances, the pitch diameter is mostly fixed for an endocutter, but the lead and tooth angle are variable. Because the upper vertebra member teeth 2450 and lower vertebra member teeth 2550 are mostly square, the rotary drive screw 2700 is more likely to be back drivable (cos (90)=1). The leads of the upper vertebra member teeth 2450 and lower vertebra member teeth 2550 may also be advantageous in that the rolling friction between the vertebra members 2420, 2520 and the rotary drive screw 2700 is more likely to enable the rotary drive screw 2700 to be back driven. Thus, in the event of an emergency, the surgeon can pull on the upper and lower cables 2404, 2504 in the proximal direction to cause the firing member 2310 to fully retract for a quick “bailout”.

As indicated above, the relative control motions for the rotary drive system 2600, as well as the various cable-management systems employed in connection with the firing system 2300 and the articulation control system 2240, may be supported within a housing 2002 which may be handheld or comprise a portion of a larger automated surgical system. The firing system 2300, articulation control system 2240, and the rotary drive system 2600 may, for example, be motor-controlled and operated by one or more control circuits.

One method of using the surgical instrument 10 may involve the use of the surgical instrument 10 to cut and staple target tissue within a patient using laparoscopic techniques. For example, one or more trocars may have been placed through the abdominal wall of a patient to provide access to a target tissue within the patient. The surgical end effector 1000 may be inserted through one trocar and one or more cameras or other surgical instruments may be inserted through the other trocar(s). To enable the surgical end effector 1000 to pass through the trocar cannula, the surgical end effector 1000 is positioned in an unarticulated orientation and the jaws 1100 and 1200 must be closed. To retain the jaws 1100 and 1200 in the closed position for insertion purposes, for example, the rotary drive system 2600 may be actuated to apply the second rotary motion to the rotary drive screw 2700 to cause the firing member 2310 to move proximally from the starting position to move the anvil 1210 (jaw 1200) to the closed position. See FIG. 44 . The rotary drive system 2600 is deactivated to retain the firing member 2310 in that position. Once the surgical end effector has passed into the abdomen through the trocar, the rotary drive system 2600 may be activated to cause the rotary drive screw 2700 to drive the firing member 2310 distally back to the starting position wherein the anvil springs 1270 will pivot the anvil 1210 to the open position. See FIG. 38 .

Once inside the abdomen and before engaging the target tissue, the surgeon may need to articulate the surgical end effector 1000 into an advantageous position. The articulation control system 2240 is then actuated to articulate the surgical end effector in one or more planes relative to a portion of the elongate shaft assembly 2000 that is received within the cannula of the trocar. Once the surgeon has oriented the surgical end effector 1000 in a desirable position, the articulation control system 2240 is deactivated to retain the surgical end effector 1000 in the articulated orientation. The surgeon may then use the surgical end effector to grasp the target tissue or adjacent tissue by activating the rotary drive system to rotate the rotary drive screw in the second rotary direction to move the firing member proximally to cause the anvil 1210 to rapidly close to grasp the tissue between the anvil 1210 and the surgical staple cartridge 1300. The anvil 1210 may be opened by reversing the rotation of the rotary drive screw 2700. This process may be repeated as necessary until the target tissue has be properly positioned between the anvil 1210 and the surgical staple cartridge 1300.

Once the target tissue has been positioned between the anvil 1210 and the surgical staple cartridge, the surgeon may commence the closing and firing process by activating the rotary drive system 2600 to drive the firing member 2310 distally from the starting position. As the firing member 2310 moves distally from the starting position, the firing member 2310 applies a closure motion to the anvil 1210 and moves the anvil 1210 from the open position to the closed position in the manners discussed above. As the firing member 2310 moves distally, the firing member 2310 retains the anvil 1210 in the closed position thereby clamping the target tissue between the anvil 1210 and the surgical staple cartridge 1300. As the firing member 2310 moves distally, the firing member 2310 contacts a sled 1312 supported in the surgical staple cartridge 1300 and also drives the sled 1312 distally through the staple cartridge body 1302. The sled 1312 serially drives rows of drivers supported in the staple cartridge toward the clamped target tissue. Each driver has supported thereon one or more surgical staples or fasteners which are then driven through the target tissue and into forming contact with the underside of the anvil 1210. As the firing member 2310 moves distally, the tissue cutting edge 2314 thereon cuts through the stapled tissue.

After the firing member 2310 has been driven distally to the ending position within the surgical end effector 1000 (FIG. 45 ), the rotary drive system 2600 is reversed which causes the firing member 2310 to retract proximally back to the home or starting position. Once the firing member 2310 has returned to the starting position, the anvil springs 1270 will pivot the anvil 1210 to the open position to enable the surgeon to release the stapled tissue from the surgical end effector 1000. Once the stapled tissue has been released, the surgical end effector may be withdrawn out of the patient through the trocar cannula. To do so, the surgeon must first actuate the articulation control system 2240 to return the surgical end effector 1000 to an unarticulated position and actuate the rotary drive system to drive the firing member 2310 proximally from the home or starting position to close the jaws. Thereafter, the surgical end effector 1000 may be withdrawn through the trocar cannula. If during the firing process or during the retraction process, the firing system becomes inoperative, the surgeon may retract the firing member 2310 back to the starting position by applying a pulling motion to the cables 2404, 2505 in the proximal direction in the various manners described herein.

FIGS. 46-68 illustrate another surgical instrument 22010 that in many aspects is identical or very similar to the surgical instrument 10 described above, except for the various differences discussed below. Like surgical instrument 10, surgical instrument 22010 may address many of the challenges facing surgical instruments with articulatable end effectors that are configured to cut and fasten tissue. In various embodiments, the surgical instrument 22010 may comprise a handheld device. In other embodiments, the surgical instrument 22010 may comprises an automated system sometimes referred to as a robotically-controlled system, for example. In various forms, the surgical instrument 22010 comprises a surgical end effector 23000 that is operably coupled to an elongate shaft assembly 24000. The elongate shaft assembly 24000 may be operably attached to a housing that is handheld or otherwise comprises a portion of a robotic system as was discussed above.

As can be seen in FIG. 49 , in one form, the surgical end effector 23000 comprises a first jaw 23100 and a second jaw 23200. In the illustrated arrangement, the first jaw 23100 comprises an elongate channel 23110 that comprises a proximal end 23112 and a distal end 23114 and is configured to operably support a surgical staple cartridge 1300 therein. The elongate channel 23110 has an open bottom to facilitate ease of assembly and has a channel cover 23113 that is configured to be attached thereto (welded, etc.) to cover the opening and add rigidity to the elongate channel 23110. In the illustrated arrangement, the second jaw 23200 comprises an anvil 23210 that comprises an elongate anvil body 23212 that comprises a proximal end 23214 and a distal end 23216. In one arrangement, an anvil cover 23213 is provided to facilitate assembly of the device and add rigidity to the anvil 23210 when it is attached (welded, etc.) to the anvil body 23212. The anvil body 23212 comprises a staple-forming undersurface 23218 that faces the first jaw 23100 and may include a series of staple-forming pockets (not shown) that corresponds to each of the staples or fasteners in the surgical staple cartridge 1300. The proximal end 23214 of the anvil body 23212 comprises an anvil mounting portion 23230 that includes a pair of laterally extending mounting pins 23232 that are configured to be received in corresponding mounting cradles or pivot cradles 23120 formed in the proximal end 23112 of the elongate channel 23110. The mounting pins 23232 are pivotally retained within the mounting cradles 23120 by an anvil cap 23260 that may be attached to the proximal end 23112 of the elongate channel 23110 by screws 23261. In other arrangements, the anvil cap 23260 may be attached to the elongate channel 23110 by welding, adhesive, etc. Such arrangement facilitates pivotal travel of the anvil 23210 relative to the surgical staple cartridge 1300 mounted in the elongate channel 23110 about a pivot axis PA between an open position (FIG. 47 ) and a closed position (FIG. 48 ). Such pivot axis PA may be referred to herein as being “fixed” in that the pivot axis does not translate or otherwise move as the anvil 23210 is pivoted from an open position to a closed position.

In the illustrated arrangement, the anvil 23210 is moved to the open position by a pair of anvil springs 23270 that are supported within the proximal end 23112 of the elongate channel 23110. See FIGS. 49 and 62 . The springs 23270 are positioned to apply a pivotal biasing force to corresponding portions of the anvil 23210 to apply opening forces thereto. See FIG. 47 .

In the illustrated arrangement, the elongate shaft assembly 24000 defines a shaft axis SA and comprises a proximal shaft portion 24100 that may operably interface with a housing of the control portion (e.g., handheld unit, robotic tool driver, etc.) of the surgical instrument 22010. The elongate shaft assembly 24000 further comprises an articulation joint 24200 that is attached to the proximal shaft portion 24100 and the surgical end effector 23000. In various instances, the proximal shaft portion 24100 comprises a hollow outer tube 24110 that may be operably coupled to a housing in the various manners discussed above. As can be seen in FIG. 49 , the proximal shaft portion 24100 may further comprise a rigid proximal support shaft 24120 that is supported within the hollow outer tube 24110 and extends from the housing to the articulation joint 24200. The rigid proximal support shaft 24120 may comprise a first half 24120A and a second half 24120B that may be coupled together by, for example, welding, adhesive, etc. The rigid proximal support shaft 24120 comprises a proximal end 24122 and a distal end 24124 and includes an axial passage 24126 that extends therethrough from the proximal end 24122 to the distal end 24124.

As was discussed above, many surgical end effectors employ a firing member that is pushed distally through a surgical staple cartridge by an axially movable firing beam. The firing beam is commonly attached to the firing member in the center region of the firing member body. This attachment location can introduce an unbalance to the firing member as it is advanced through the end effector. Such unbalance can lead to undesirable friction between the firing member and the end effector jaws. The creation of this additional friction may require an application of a higher firing force to overcome such friction as well as can cause undesirable wear to portions of the jaws and/or the firing member. An application of higher firing forces to the firing beam may result in unwanted flexure in the firing beam as it traverses the articulation joint. Such additional flexure may cause the articulation joint to de-articulate—particularly when the surgical end effector is articulated at relatively high articulation angles. The surgical instrument 22010 employs a firing system 24300 that is identical to or very similar in many aspects as firing system 2300 described above. As such, only those aspects of the firing system 24300 needed to understand the operation of the surgical instrument 22010 will be discussed below.

As can be seen in FIGS. 50-54 , in at least one embodiment, the firing system 24300 comprises a firing member 24310 that includes a vertically-extending firing member body 24312 that comprises a top firing member feature 24320 and a bottom firing member feature 24350. A tissue cutting blade 24314 is attached to or formed in the vertically-extending firing member body 24312. See FIGS. 50 and 51 . In at least one arrangement, it is desirable for the firing member 24310 to pass through the anvil body 23212 with low friction, high strength and high stiffness. In the illustrated arrangement, the top firing member feature 24320 comprises a T-shaped body 24322 that has two laterally extending tabs 24323 protruding therefrom and a top axial passage 24324 extending therethrough. See FIG. 53 . The bottom firing member feature 24350 comprises a T-shaped body 24352 that has two laterally extending tabs 24353 protruding therefrom and a bottom axial passage 24354 extending therethrough. See FIG. 50 . In at least one arrangement, the top firing member feature 24320 and the bottom firing member feature 24350 are integrally formed with the vertically-extending firing member body 24312. As can be seen in FIG. 54 , the anvil body 23212 comprises an axially extending anvil slot 23240 that defines two opposed ledges 23241 for slidably receiving the laterally extending tabs 24323 thereon. Similarly, the elongate channel 23110 comprises an axially extending channel slot 23140 that defines axially extending channel ledges 23141 that are configured to slidably receive the laterally extending tabs 24353 thereon.

In the illustrated arrangement, the firing system 24300 comprises an upper flexible spine assembly 24400 that is operably coupled to the top firing member feature 24320 of the firing member 24310. In at least one embodiment, the upper flexible spine assembly 24400 comprises an upper series 24410 of upper vertebra members 24420 that are loosely coupled together by an upper flexible coupler member 24440 that extends through each of the upper vertebra members 24420 and is attached to the top firing member feature 24320.

As can be seen in FIG. 52 , each upper vertebra member 24420 is substantially T-shaped when viewed from an end thereof. In one aspect, each upper vertebra member 24420 comprises an upper vertebra body portion 24422 that has a proximal end 24424 and a distal end 24428. Each upper vertebra member 24420 further comprises a downwardly extending upper drive feature or upper vertebra member tooth 24450 that protrudes from the upper vertebra body portion 24422. Each upper vertebra member tooth 24450 has a helix-shaped proximal upper face portion 24452 and a helix-shaped distal upper face portion 24454. Each proximal end 24424 of the upper vertebra body portions 24422 has an arcuate or slightly concave curved shape and each distal end 24428 has an arcuate or slightly convex curved shape. When arranged in the upper series 24410, the convex distal end 24428 on one upper vertebra member 24420 contacts and mates with the concave proximal end 24424 on an adjacent upper vertebra member 24420 in the upper series 24410 to maintain the upper vertebra members 24420 roughly in alignment so that the helix-shaped proximal upper face portion 24452 and a helix-shaped distal upper face portion 24454 on each respective upper vertebra member tooth 24450 can be drivingly engaged by a rotary drive screw 2700 in the various manners disclosed herein. These curved mating surfaces on the upper vertebra members 24420 allow the upper vertebras members 24420 to better transfer loads between themselves even when they tilt.

In at least one embodiment, an upper alignment member 24480 is employed to assist with the alignment of the upper vertebra members 24420 in the upper series 24410. In one arrangement, the alignment member 24480 comprises a spring member or metal cable which may be fabricated from Nitinol wire, spring steel, etc., and be formed with a distal upper looped end 24482 and two upper leg portions 24484 that extend through corresponding upper passages 24425 in each upper vertebra body portion 24422. The upper flexible coupler member 24440 extends through an upper passage 24429 in each of the upper vertebra members 24420 to be attached to the firing member 24310. In particular, a distal end portion 24442 extends through the top axial passage 24324 in the top firing member feature 24320 and is secured therein by an upper retention lug 24444. A proximal portion of the upper flexible coupler member 24440 may interface with a corresponding rotary spool or cable-management system of the various types and designs disclosed herein that serve to payout and take up the upper flexible coupler member 24440 to maintain a desired amount of tension therein during operation and articulation of the surgical end effector 23000. The cable management system may be motor powered or manually powered (ratchet arrangement, etc.) to maintain a desired amount of tension in the upper flexible coupler member 24440. The amount of tension in each flexible coupler member may vary depending upon the relative positioning of the surgical end effector 23000 to the elongate shaft assembly 24000.

The firing system 24300 further comprises a lower flexible spine assembly 24500 that is operably coupled to the bottom firing member feature 24350. The lower flexible spine assembly 24500 comprises a lower series 24510 of lower vertebra members 24520 that are loosely coupled together by a lower flexible coupler member 24540 that extends through each of the lower vertebra members 24520 and is attached to the bottom firing member feature 24350. As can be seen in FIG. 52 , each lower vertebra member 24520 is substantially T-shaped when viewed from an end thereof. In one aspect, each lower vertebra member 24520 comprises a lower vertebra body portion 24522 that has a proximal end 24524 and a distal end 24528. Each lower vertebra member 24520 further comprises an upwardly extending lower drive feature or lower vertebra member tooth 24550 that protrudes from the lower vertebra body portion 24522. Each lower vertebra member tooth 24550 has a helix-shaped proximal lower face portion 24552 and a helix-shaped distal lower face portion 24554. The proximal end 24524 of each lower vertebra body portions 24522 has an arcuate or slightly concave curved shape and each distal end 24528 has an arcuate or slightly convex curved shape. When arranged in the lower series 24510, the convex distal end 24528 on one lower vertebra member 24520 contacts and mates with the concave proximal end 24524 on an adjacent lower vertebra member 24520 in the lower series 24510 to maintain the lower vertebra members 24520 roughly in alignment so that the helix-shaped proximal lower face portion 24552 and a helix-shaped distal lower face portion 24554 on each respective lower vertebra member tooth 24550 can be drivingly engaged by the rotary drive screw 2700 in the various manners disclosed herein. These curved mating surfaces on the lower vertebra members 24520 allow the lower vertebra members 24520 to better transfer loads between themselves even when they tilt.

In at least one embodiment, a lower alignment member 24580 is employed to assist with the alignment of the lower vertebra members 24520 in the lower series 24510. In one arrangement, the lower alignment member 24580 comprises a spring member or metal cable which may be fabricated from Nitinol wire, spring steel, etc., and be formed with a distal lower looped end 24582 and two lower leg portions 24584 that extend through corresponding lower passages 24525 in each lower vertebra body portion 24522. The lower flexible coupler member 24540 extends through the bottom axial passage 24529 in each of the lower vertebra members 24520 to be attached to the firing member 24310. In particular, a distal end portion 24542 of the lower flexible coupler member 24540 extends through the bottom axial passage 24354 in the bottom firing member feature 24350 and is secured therein by a lower retention lug 24544. A proximal portion of the lower flexible coupler member 24540 may interface with a corresponding rotary spool or cable-management system of the various types and designs disclosed herein that serve to payout and take up the lower flexible coupler member 24540 to maintain a desired amount of tension therein during operation and articulation of the surgical end effector 23000. The cable management system may be motor powered or manually powered (ratchet arrangement, etc.) to maintain a desired amount of tension in the lower flexible coupler member 24540. The amount of tension in each flexible coupler member may vary depending upon the relative positioning of the surgical end effector 23000 to the elongate shaft assembly 24000.

In accordance with at least one aspect, a large surface area is advantageous for distributing the force between the vertebra members when they push so that the vertebra members cannot twist relative to each other. The available area in the anvil and channel is limited and the anvil and channel must remain stiff. The T-shaped upper vertebra members 24420 and the T-shaped lower vertebra members 24520 are designed to fit in the limited spaces available in the anvil 23210 and the elongate channel 23110 while ensuring that there is a large amount of area to distribute the firing loads. The curved surfaces on each upper vertebra member 24420 and each lower vertebra member 24520 allow each of those vertebras to better transfer loads between themselves even when they tilt. The upper alignment member 24480 and the lower alignment member 24580 may also serve to prevent the upper vertebra members 24420 and the lower vertebra members 24520 from twisting relative to each other. The large surface area may also help to prevent galling of the vertebra members and/or the anvil and channel. The upper flexible spine assembly 24400 and the lower flexible spine assembly 24500 otherwise operably interface with the rotary drive screw 2700 arrangements as disclosed herein. The upper flexible coupler member 24440 and the lower flexible coupler member 24540 may also be used in the manners discussed above to retract the firing member 24310 back to its starting position if, during a firing stroke, the firing drive system 24300 fails.

As can be seen in FIG. 51 , the top firing member feature 24320 on the firing member 24310 comprises a distal upper firing member tooth segment 24330 that is equivalent to one half of an upper vertebra member tooth 24450 on each upper vertebra member 24420. In addition, two proximal upper firing member teeth 24336 that are identical to an upper vertebra member tooth 24450 on each upper vertebra member 24420 are spaced from the distal upper firing member tooth segment 24330. The distal upper firing member tooth segment 24330 and the proximal upper firing member teeth 24336 may each be integrally formed with the top firing member feature 24320 of the firing member 24310. Likewise, the bottom firing member feature 24350 of the firing member 24310 comprises a distal lower firing member tooth 24360 and two proximal lower firing member teeth 24366 that are integrally formed on the bottom firing member feature 24350. For example, in at least one arrangement, the firing member 24310 with the rigidly attached teeth 24330, 24336, 24360, and 24366 may be fabricated at one time as one unitary component using conventional metal injection molding techniques. The person of ordinary skill in the art will recognize that the firing member 24310 operates in essentially the same manner as the firing member 2310 as was described in detail herein.

Turning now to FIGS. 55-58 , in accordance with at least one aspect, the articulation joint 24200 comprises a movable exoskeleton assembly 24800. In one form, the movable exoskeleton assembly 24800 comprises a series 24802 of movably interfacing annular rib members 24810. As can be seen in FIGS. 55-57 , each annular rib member 24810 comprises a first or proximal face 24820 that comprises a convex or domed portion 24822. Each annular rib member 24810 further comprises a second or distal face 24830 that is concave or dished. Each annular rib member 24810 further comprises an upper spine passage 24840 that is configured to accommodate passage of the upper flexible spine assembly 24400 therethrough and a lower spine passage 24842 that is configured to accommodate passage of the lower flexible spine assembly 24500 therethrough. In addition, each annular rib member 24810 further comprises four articulation passages 24850, 24852, 24854, and 24856 to accommodate passage of articulation actuators in the form of articulation cables 24242, 22446, 24250, and 24254 therethrough. See FIG. 49 . Each annular rib member 24810 further comprises a central drive passage 24860 that is configured to accommodate passage of the constant velocity (CV) drive shaft assembly 2620 therethrough.

As can be seen in FIG. 58 , the movable exoskeleton assembly 24800 comprises a proximal attachment rib 24870 that is configured to attach the movable exoskeleton assembly 24800 to the distal end 24124 of the proximal support shaft 24120 by cap screws 24880 or other suitable fastener arrangements. The proximal attachment rib 24870 comprises a first or distal face 24872 that is concave or dished to receive or movably interface with the convex or domed portion 24822 of the proximal face 24820 of a proximal-most annular rib member 24810P. Similarly, the movable exoskeleton assembly 24800 comprises a distal attachment rib 24890 that is configured to attach the movable exoskeleton assembly 24800 to the proximal end 23112 of the elongate channel 23110 by cap screws 24882 or other suitable fasteners. The distal attachment rib 24890 comprises a first or proximal face 24892 that comprises a convex or domed portion 24894 that configured to be received in or movably interface with the concave or dished distal face 24832 of a distal-most annular rib member 24810D. In various embodiments, the annular rib members 24810, 24810P, and 24810D may be fabricated from any suitable metal (e.g., stainless steel, titanium, etc.) or other suitable material. The annular rib members 24810, 24810P, and 24810D may be formed by suitable drawing or forming operations, by machining or casting. The proximal faces 24820 and the distal faces 24830 may be polished or otherwise finished to a desirable smooth finish to reduce friction and facilitate movement between the annular rib members 24810, 24810P, and 24810D. In accordance with one aspect, all edges on each annular rib member 24810, 24810P, 24810D are rounded to facilitate relative movement between the annular rib members. The proximal attachment rib 24870 and the distal attachment rib 24890 may be formed with similar attributes.

The surgical instrument 22010 also comprises an articulation system 24240 that is configured to apply articulation motions to the surgical end effector 23000 to articulate the surgical end effector 23000 relative to the elongate shaft assembly 24000. In at least one arrangement, for example, as mentioned above, the articulation system 24240 comprises four articulation cables 24242, 24246, 24250, and 24254 that extend through the elongate shaft assembly 2400. See FIG. 49 . In the illustrated arrangement, the articulation cables 24242, 24246 pass through the proximal attachment rib 24870 and through each of the annular rib members 24810P, 24810, and 24810D to be secured to the distal attachment rib 24890. In one arrangement for example, each of the articulation cables 24242, 24246 are secured to the distal attachment rib 24890 by corresponding attachment lugs 24243. See FIGS. 61 and 63 . Likewise, the articulation cables 24250 and 24254 extend through the proximal attachment rib 24870 and through each of the annular rib members 24810P, 24810, and 24810D to be secured to the distal attachment rib 24890 by corresponding attachment lugs 24243.

In one arrangement, each of the articulation cables 24242, 24246, 24250, and 24254 extend through corresponding coil springs 24896 that are supported in cavities 24125 in the distal end 24124 of the rigid proximal support shaft 24120. In addition, each coil spring 24896 is associated with a tensioning lug 24897 that is also journaled onto each respective articulation cable 24242, 24246, 24250, and 24524 and is secured thereon to attain a desired amount of compression in each spring 24896 which serves to retain the annular rib members 24810P, 24810, and 24810D in movable engagement with each other and with the proximal attachment rib 24870 and the distal attachment rib 24890. The cables 24242, 24246, 24250, and 24254 operably interface with an articulation control system that is supported in the housing of the surgical instrument 22010. For example, as was discussed above, a proximal portion of each cable 24242, 24246, 24250, and 24254 may be spooled on a corresponding rotary spool or cable-management system 2007 (FIG. 2 ) in the housing portion of the surgical instrument 22010 that is configured to payout and retract each cable 24242, 24246, 24250, and 24254 in desired manners. The spools/cable management system may be motor powered or manually powered (ratchet arrangement, etc.). FIG. 59 illustrates the articulation joint 24200 in an unarticulated position and FIG. 60 illustrates the articulation joint in one articulated configuration. Such arrangement permits the surgical end effector 23000 to be articulated through multiple articulation planes relative to the elongate shaft assembly 24000.

As can be seen in FIGS. 49, 58, and 64 , the surgical instrument 22010 employs a constant velocity (CV) drive shaft assembly 2620 that spans or extends axially through the articulation joint 24200. The operation and construction of the CV drive shaft assembly 2620 was described in detail above and will not be repeated here beyond what is necessary to understand the operation of the surgical instrument 22010. Briefly as described above, the CV drive shaft assembly 2620 comprises a proximal CV drive assembly 2630 and a distal CV drive shaft 2670. The proximal CV drive assembly 2630 comprises a proximal shaft segment 2632 that consists of an attachment shaft 2634 that is configured to be non-rotatably received within a similarly-shaped coupler cavity 2616 in the distal end 2614 of the proximal rotary drive shaft 2610. The proximal shaft segment 2632 operably interfaces with a series 2640 of movably coupled drive joints 2650. As can be seen in FIG. 58 as was also described previously, to ensure that the drive joints 2650 are engaged with each other, a proximal drive spring 2740 is employed to apply an axial biasing force to the series 2640 of drive joints 2650. For example, as can be seen in FIG. 58 , proximal drive spring 2740 is positioned between the proximal mounting bushing 2734 and a support flange that is formed between the distal socket portion 2636 and a proximal barrel portion 2638 of the proximal shaft segment 2632. In one arrangement, the proximal drive spring 2740 may comprise an elastomeric O-ring received on the proximal barrel portion 2638 of the proximal shaft segment 2632. The proximal drive spring 2740 lightly biases the drive joints 2650 together to decrease any gaps that occur during articulation. This ensures that the drive joints 2650 transfer loads torsionally. It will be appreciated, however, that in at least one arrangement, the proximal drive spring 2740 does not apply a high enough axial load to cause firing loads to translate through the articulation joint 2200.

To further prevent the drive joints 2650 from buckling during articulation, the series 2640 of movably coupled drive joints 2650 extend through at least one low friction drive cover 24730 that extends through the central drive passage 24860 in each of the annular rib members 24810. In the arrangement depicted in FIGS. 63 and 65 , the drive cover 24730 comprises an outer and inner cut hypotube 24732. Such hypotube 24732 may be fashioned from metal (e.g., stainless steel, etc.) and have multiple series of cuts or slits therein that may be made using laser cutter arrangements. In the illustrated arrangement, the hypotube 24732 may be fabricated with an upper relief passage 24734 that provides clearance for the upper flexible spine assembly 24400 to pass thereover during operation while the surgical end effector 23000 is in an articulated position and articulated positions. In addition, the hypotube 24732 may have a lower relief passage 24736 to provide similar clearance for the lower flexible spine assembly 24500. As can also be seen in FIG. 65 , the hypotube 24732 may be shaped with diametrically opposed lateral tab portions 24738 to provide lateral stability during articulation. FIG. 66 illustrates an alternative drive cover 24730′ that comprises an inner cut hypotube 24732′. FIGS. 58, 67, 68 , and 69 illustrate an alternative drive cover 24730″ that comprises flexible heat shrink tubing 24732″ that is applied over the constant velocity (CV) drive shaft assembly 2620. In still other arrangements, the drive cover may comprise a coiled spring or coiled member as well.

Various embodiments of the present disclosure provide advantages over previous surgical endocutter configurations that are capable of articulation. For example, pushing a firing member forward in an articulating end effector generally requires a lot of force and that force must be balanced. For example, when firing the firing member at an angle of greater than sixty degrees, it becomes very difficult to push a beam through the articulation joint. The joint also experiences significant loads which may cause the articulation joint to de-articulate. By employing an upper flexible drive arrangement and a lower flexible drive arrangement that are each flexible through the articulation joint, but then become rigid when they are distal to the articulation joint can allow for a large degree of articulation (e.g., articulation angles over seventy degrees) while applying balanced loads to the firing member that are constrained to the firing member and not to the articulation joint. Stated another way, torsional loads are applied proximal to the articulation joint instead of longitudinal loads which could lead to de-articulation of the end effector. The torsional loads are converted to longitudinal loads at a position that is distal to the articulation joint. Thus, the rotary drive screw serves to actually convert torsional motion or loads to longitudinal loads that are applied to the firing member at a location that is distal to the articulation joint.

Further, by longitudinally breaking up the threaded drive arrangements, the threaded drive arrangements pass through the articulation joint while also effectively decreasing the length of the surgical end effector. For example, each single vertebra tooth is significantly shorter than multiple pitches rigidly connected. The vertebra can angle as they pass through the articulation joint. This flexible interconnection enables the rotary drive screw to be closely positioned to the articulation joint as compared to being significantly spaced therefrom if all of the pitches were rigidly connected.

Example 1—A surgical instrument comprising an elongate shaft. A surgical end effector is coupled to the elongate shaft by an articulation joint that is configured to facilitate selective articulation of the surgical end effector relative to the elongate shaft. The surgical end effector comprises a first jaw and a second jaw that is configured to move relative to the first jaw between an open position and a closed position. A firing member is supported for axial travel within the surgical end effector between a starting position and an ending position. The surgical instrument further comprises an upper flexible spine assembly that is attached to a top portion of the firing member. A lower flexible spine assembly is attached to a bottom portion of the firing member. A rotary drive member operably interfaces with the upper flexible spine assembly at an upper location. The rotary drive member also operably interfaces with the lower flexible spine assembly at a lower location. The upper location and the lower location are distal to the articulation joint. The rotary drive member is configured to cause the upper flexible spine assembly and the lower flexible spine assembly to apply axial drive motions to the firing member to move the firing member between the starting position and the ending position.

Example 2—The surgical instrument of Example 1, wherein the rotary drive member is centrally disposed between the upper flexible spine assembly and the lower flexible spine assembly.

Example 3—The surgical instrument of Examples 1 or 2, wherein the upper flexible spine assembly comprises an upper series of upper vertebra members that are loosely coupled together and the lower flexible spine assembly comprises a lower series of lower vertebra members that are loosely coupled together.

Example 4—The surgical instrument of Example 3, wherein the upper vertebra members are movably supported relative to each other by an upper flexible coupler member that is coupled to the top portion of the firing member and extends through each upper vertebra member. The lower vertebra members are movably supported relative to each other by a lower flexible coupler member that is coupled to the bottom portion of the firing member and extends through each lower vertebra member.

Example 5—The surgical instrument of Example 4, wherein each upper vertebra member comprises an upper vertebra body portion that defines an upper proximal end and an upper distal end. An upper hollow passage extends through the upper vertebra body portion between the upper proximal end and the upper distal end to permit the upper flexible coupler member to extend therethrough. An upper proximal mating feature is provided on the upper proximal end and an upper distal mating feature is provided on the upper distal end. The upper proximal mating feature on each upper vertebra member is configured to movably interface with the upper distal mating feature on an adjacent upper vertebra member. An upper vertebra drive feature is configured to operably engage the rotary drive member.

Example 6—The surgical instrument of Example 5, wherein the upper proximal mating feature comprises an upper concave recess in the upper proximal end of the upper vertebra body portion. The upper distal mating feature comprises an upper convex protrusion on the upper distal end of the upper vertebra body portion. The upper convex protrusion on each upper vertebra member is sized and shaped to matingly engage the upper concave recess in an adjacent upper vertebra member.

Example 7—The surgical instrument of Examples 5 or 6, wherein the each lower vertebra member comprises a lower vertebra body portion that defines a lower proximal end and a lower distal end. A lower hollow passage extends through the lower vertebra body portion between the lower proximal end and the lower distal end to permit the lower flexible coupler member to extend therethrough. A lower proximal mating feature is provided on the lower proximal end and a lower distal mating feature is provided on the lower distal end. The lower proximal mating feature on each lower vertebra member is configured to movably interface with the lower distal mating feature on an adjacent lower vertebra member. A lower vertebra drive feature is configured to operably engage the rotary drive member.

Example 8—The surgical instrument of Example 7, wherein the lower proximal mating feature comprises a lower concave recess in the lower proximal end of the lower vertebra body portion and the lower distal mating feature comprises a lower convex protrusion on the lower distal end of the lower vertebra body portion. The lower convex protrusion on each lower vertebra member is sized and shaped to matingly engage the lower concave recess in an adjoining lower vertebra member.

Example 9—The surgical instrument of Examples 7 or 8, wherein the upper vertebra drive feature comprises an upper tooth that is configured to interface with the rotary drive member, and wherein the lower vertebra drive feature comprises a lower tooth that is configured to interface with the rotary drive member.

Example 10—The surgical instrument of Example 9, wherein the rotary drive member comprises a rotary body portion that has a helical drive member on an external surface thereof. The helical drive member is configured to engage an upper helical surface that is formed on each upper tooth and a lower helical surface on each lower tooth.

Example 11—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9 or 10, further comprising an upper vertebra biaser that is configured to apply a continuous upper compression to the upper series of upper vertebra members to retain the upper vertebra members in the upper series of upper vertebra members in movable contact with each other. The surgical instrument further comprises a lower vertebra biaser that is configured to apply a continuous lower compression to the lower series of lower vertebra members to retain the lower vertebra members in the lower series of lower vertebra members in movable contact with each other.

Example 12—The surgical instrument of Example 10, wherein the upper helical surface comprises two different pitches.

Example 13—The surgical instrument of Examples 4, 5, 6, 7, 8, 9, 10, 11 or 12, wherein the upper flexible coupler member and the lower flexible coupler member are configured to retract the firing member from a position that is distal to the starting position by applying retraction motions to each of the upper flexible coupler member and the lower flexible coupler member in a proximal direction.

Example 14—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, wherein the articulation joint comprises an articulation joint length and wherein the upper series of upper vertebra members comprises an upper series length that is greater than or equal to the articulation joint length plus a distance from the starting position to the ending position of the firing member. The lower series of lower vertebra members comprises a lower series length that is greater than or equal to the articulation joint length plus the distance from the starting position to the ending position of the firing member.

Example 15—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, further comprising an upper sleeve that extends from a proximal end of the surgical end effector and spans the articulation joint. The upper sleeve is axially movable relative to the surgical end effector and is configured to slidably support a portion of the upper series of upper vertebra members that spans the articulation joint. A lower sleeve extends from the proximal end of the surgical end effector and spans the articulation joint. The lower sleeve is axially movable relative to the surgical end effector and is configured to slidably support another portion of the lower series of lower vertebra members that spans the articulation joint.

Example 16—A surgical instrument that comprises an elongate shaft that has a surgical end effector coupled thereto by an articulation joint that is configured to facilitate selective articulation of the surgical end effector relative to the elongate shaft. The surgical end effector comprises a firing member that is supported for axial travel within the surgical end effector between a starting position and an ending position. A rotary drive member is rotatably supported at a location that is distal to the articulation joint. An upper longitudinally-segmented nut assembly is attached to a top portion of the firing member and is in threaded engagement with the rotary drive member at an upper location that is distal to the articulation joint such that rotation of the rotary drive member causes the upper longitudinally-segmented nut assembly to apply an upper axial drive motion to the firing member. The upper longitudinally-segmented nut assembly is flexible to accommodate articulation of the surgical end effector. A lower longitudinally-segmented nut assembly is attached to a bottom portion of the firing member and is in threaded engagement with the rotary drive member at a lower location that is distal to the articulation joint such that rotation of the rotary drive member causes the lower longitudinally-segmented nut assembly to apply a lower axial drive motion to the firing member. The lower longitudinally-segmented nut assembly is flexible to accommodate articulation of the surgical end effector.

Example 17—The surgical instrument of Example 16, wherein the upper longitudinally-segmented nut assembly comprises an upper series of upper vertebra members that are movably supported relative to each other by an upper flexible coupler member that is coupled to the top portion of the firing member and extends through each upper vertebra member. The lower longitudinally-segmented nut assembly comprises a lower series of lower vertebra members that are movably supported relative to each other by a lower flexible coupler member that is coupled to the bottom portion of the firing member and extends through each lower vertebra member.

Example 18—The surgical instrument of Examples 16 or 17, wherein the rotary drive member comprises a helical thread that comprises at least two different pitches.

Example 19—The surgical instrument of Examples 17 or 18, further comprising means for permitting the upper vertebra members and the lower vertebra members that traverse the articulation joint to move out of axial alignment while facilitating serial threaded engagement with the rotary drive member.

Example 20—A surgical instrument that comprises an elongate shaft that has a surgical end effector coupled thereto by an articulation joint configured to facilitate selective articulation of the surgical end effector relative to the elongate shaft. The surgical end effector comprises a firing member that is supported for axial travel within the surgical end effector between a starting position and an ending position. A rotary drive member is rotatably supported at a location that is distal to the articulation joint. A flexible drive assembly is supported by the elongate shaft such that it axially traverses the articulation joint and is configured to accommodate articulation of the surgical end effector about the articulation joint. The flexible drive assembly is in threaded engagement with the rotary drive member at a drive location that is distal to the articulation joint such that rotation of the rotary drive member causes the flexible drive assembly to apply an axial drive motion to the firing member.

As used in any aspect herein, the term “control circuit” may refer to, for example, hardwired circuitry, programmable circuitry (e.g., a computer processor including one or more individual instruction processing cores, processing unit, processor, microcontroller, microcontroller unit, controller, digital signal processor (DSP), programmable logic device (PLD), programmable logic array (PLA), or field programmable gate array (FPGA)), state machine circuitry, firmware that stores instructions executed by programmable circuitry, and any combination thereof. The control circuit may, collectively or individually, be embodied as circuitry that forms part of a larger system, for example, an integrated circuit (IC), an application-specific integrated circuit (ASIC), a system on-chip (SoC), desktop computers, laptop computers, tablet computers, servers, smart phones, etc. Accordingly, as used herein “control circuit” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof.

While several forms have been illustrated and described, it is not the intention of Applicant to restrict or limit the scope of the appended claims to such detail. Numerous modifications, variations, changes, substitutions, combinations, and equivalents to those forms may be implemented and will occur to those skilled in the art without departing from the scope of the present disclosure. Moreover, the structure of each element associated with the described forms can be alternatively described as a means for providing the function performed by the element. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications, combinations, and variations as falling within the scope of the disclosed forms. The appended claims are intended to cover all such modifications, variations, changes, substitutions, modifications, and equivalents.

One or more components may be referred to herein as “configured to,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that “configured to” can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise.

Those skilled in the art will recognize that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.”

With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flow diagrams are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,” “an exemplification,” “one exemplification,” and the like means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases “in one aspect,” “in an aspect,” “in an exemplification,” and “in one exemplification” in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.

Any patent application, patent, non-patent publication, or other disclosure material referred to in this specification and/or listed in any Application Data Sheet is incorporated by reference herein, to the extent that the incorporated materials is not inconsistent herewith. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

In summary, numerous benefits have been described which result from employing the concepts described herein. The foregoing description of the one or more forms has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more forms were chosen and described in order to illustrate principles and practical application to thereby enable one of ordinary skill in the art to utilize the various forms and with various modifications as are suited to the particular use contemplated. It is intended that the claims submitted herewith define the overall scope.

The surgical instrument systems described herein have been described in connection with the deployment and deformation of staples; however, the embodiments described herein are not so limited. Various embodiments are envisioned which deploy fasteners other than staples, such as clamps or tacks, for example. Moreover, various embodiments are envisioned which utilize any suitable means for sealing tissue. For instance, an end effector in accordance with various embodiments can comprise electrodes configured to heat and seal the tissue. Also, for instance, an end effector in accordance with certain embodiments can apply vibrational energy to seal the tissue.

Many of the surgical instrument systems described herein are motivated by an electric motor; however, the surgical instrument systems described herein can be motivated in any suitable manner. In various instances, the surgical instrument systems described herein can be motivated by a manually-operated trigger, for example. In certain instances, the motors disclosed herein may comprise a portion or portions of a robotically controlled system. Moreover, any of the end effectors and/or tool assemblies disclosed herein can be utilized with a robotic surgical instrument system. U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, for example, discloses several examples of a robotic surgical instrument system in greater detail.

The entire disclosures of:

U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995;

U.S. Pat. No. 7,000,818, entitled SURGICAL STAPLING INSTRUMENT HAVING SEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, which issued on Feb. 21, 2006;

U.S. Pat. No. 7,422,139, entitled MOTOR-DRIVEN SURGICAL CUTTING AND FASTENING INSTRUMENT WITH TACTILE POSITION FEEDBACK, which issued on Sep. 9, 2008;

U.S. Pat. No. 7,464,849, entitled ELECTRO-MECHANICAL SURGICAL INSTRUMENT WITH CLOSURE SYSTEM AND ANVIL ALIGNMENT COMPONENTS, which issued on Dec. 16, 2008;

U.S. Pat. No. 7,670,334, entitled SURGICAL INSTRUMENT HAVING AN ARTICULATING END EFFECTOR, which issued on Mar. 2, 2010;

U.S. Pat. No. 7,753,245, entitled SURGICAL STAPLING INSTRUMENTS, which issued on Jul. 13, 2010;

U.S. Pat. No. 8,393,514, entitled SELECTIVELY ORIENTABLE IMPLANTABLE FASTENER CARTRIDGE, which issued on Mar. 12, 2013;

U.S. patent application Ser. No. 11/343,803, entitled SURGICAL INSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Pat. No. 7,845,537;

U.S. patent application Ser. No. 12/031,573, entitled SURGICAL CUTTING AND FASTENING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008;

U.S. patent application Ser. No. 12/031,873, entitled END EFFECTORS FOR A SURGICAL CUTTING AND STAPLING INSTRUMENT, filed Feb. 15, 2008, now U.S. Pat. No. 7,980,443;

U.S. patent application Ser. No. 12/235,782, entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT, now U.S. Pat. No. 8,210,411;

U.S. patent application Ser. No. 12/235,972, entitled MOTORIZED SURGICAL INSTRUMENT, now U.S. Pat. No. 9,050,083;

U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICAL CUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM, now U.S. Pat. No. 8,608,045;

U.S. patent application Ser. No. 12/647,100, entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT WITH ELECTRIC ACTUATOR DIRECTIONAL CONTROL ASSEMBLY, filed Dec. 24, 2009, now U.S. Pat. No. 8,220,688;

U.S. patent application Ser. No. 12/893,461, entitled STAPLE CARTRIDGE, filed Sep. 29, 2012, now U.S. Pat. No. 8,733,613;

U.S. patent application Ser. No. 13/036,647, entitled SURGICAL STAPLING INSTRUMENT, filed Feb. 28, 2011, now U.S. Pat. No. 8,561,870;

U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535;

U.S. patent application Ser. No. 13/524,049, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, filed on Jun. 15, 2012, now U.S. Pat. No. 9,101,358;

U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat. No. 9,345,481;

U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Patent Application Publication No. 2014/0263552;

U. S. Patent Application Publication No. 2007/0175955, entitled SURGICAL CUTTING AND FASTENING INSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM, filed Jan. 31, 2006; and

U. S. Patent Application Publication No. 2010/0264194, entitled SURGICAL STAPLING INSTRUMENT WITH AN ARTICULATABLE END EFFECTOR, filed Apr. 22, 2010, now U.S. Pat. No. 8,308,040, are hereby incorporated by reference herein.

Although various devices have been described herein in connection with certain embodiments, modifications and variations to those embodiments may be implemented. Particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined in whole or in part, with the features, structures or characteristics of one or more other embodiments without limitation. Also, where materials are disclosed for certain components, other materials may be used. Furthermore, according to various embodiments, a single component may be replaced by multiple components, and multiple components may be replaced by a single component, to perform a given function or functions. The foregoing description and following claims are intended to cover all such modification and variations.

The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, a device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps including, but not limited to, the disassembly of the device, followed by cleaning or replacement of particular pieces of the device, and subsequent reassembly of the device. In particular, a reconditioning facility and/or surgical team can disassemble a device and, after cleaning and/or replacing particular parts of the device, the device can be reassembled for subsequent use. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.

The devices disclosed herein may be processed before surgery. First, a new or used instrument may be obtained and, when necessary, cleaned. The instrument may then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument may then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, and/or high-energy electrons. The radiation may kill bacteria on the instrument and in the container. The sterilized instrument may then be stored in the sterile container. The sealed container may keep the instrument sterile until it is opened in a medical facility. A device may also be sterilized using any other technique known in the art, including but not limited to beta radiation, gamma radiation, ethylene oxide, plasma peroxide, and/or steam.

While this invention has been described as having exemplary designs, the present invention may be further modified within the spirit and scope of the disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. 

What is claimed is:
 1. A surgical instrument, comprising: an elongate shaft; a surgical end effector coupled to said elongate shaft by an articulation joint, wherein said articulation joint is configured to facilitate selective articulation of said surgical end effector relative to said elongate shaft, and wherein said surgical end effector comprises: a first jaw; a second jaw, wherein said second jaw is configured to move relative to said first jaw between an open position and a closed position; and a firing member supported for axial travel within said surgical end effector between a starting position and an ending position, and wherein said surgical instrument further comprises: an upper flexible spine assembly attached to a top portion of said firing member; a lower flexible spine assembly attached to a bottom portion of said firing member; and a rotary drive member, wherein said rotary drive member operably interfaces with said upper flexible spine assembly at an upper location, wherein said rotary drive member operably interfaces with said lower flexible spine assembly at a lower location, wherein said upper location and said lower location are distal to said articulation joint, and wherein said rotary drive member causes said upper flexible spine assembly and said lower flexible spine assembly to apply axial drive motions to said firing member to move said firing member between said starting position and said ending position.
 2. The surgical instrument of claim 1, wherein said rotary drive member is centrally disposed between said upper flexible spine assembly and said lower flexible spine assembly.
 3. The surgical instrument of claim 1, wherein said upper flexible spine assembly comprises an upper series of upper vertebra members that are loosely coupled together, and wherein said lower flexible spine assembly comprises a lower series of lower vertebra members that are loosely coupled together.
 4. The surgical instrument of claim 3, wherein said upper vertebra members are movably supported relative to each other by an upper flexible coupler member that is coupled to said top portion of said firing member and extends through each said upper vertebra member, and wherein said lower vertebra members are movably supported relative to each other by a lower flexible coupler member that is coupled to said bottom portion of said firing member and extends through each lower vertebra member.
 5. The surgical instrument of claim 4, wherein each said upper vertebra member comprises: an upper vertebra body portion, wherein said upper vertebra body portion defines an upper proximal end and an upper distal end; an upper hollow passage in said upper vertebra body portion, wherein said upper hollow passage extends through said upper vertebra body portion between said upper proximal end and said upper distal end to permit said upper flexible coupler member to extend therethrough; an upper proximal mating feature on said upper proximal end; an upper distal mating feature on said upper distal end, wherein said upper proximal mating feature on each said upper vertebra member is configured to movably interface with said upper distal mating feature on an adjacent said upper vertebra member; and an upper vertebra drive feature configured to operably engage said rotary drive member.
 6. The surgical instrument of claim 5, wherein said upper proximal mating feature comprises an upper concave recess in said upper proximal end of said upper vertebra body portion, wherein said upper distal mating feature comprises an upper convex protrusion on said upper distal end of said upper vertebra body portion, and wherein said upper convex protrusion on each said upper vertebra member is sized and shaped to matingly engage said upper concave recess in said adjacent said upper vertebra member.
 7. The surgical instrument of claim 5, wherein each said lower vertebra member comprises: a lower vertebra body portion, wherein said lower vertebra body portion defines a lower proximal end and a lower distal end; a lower hollow passage in said lower vertebra body portion, wherein said lower hollow passage extends through said lower vertebra body portion between said lower proximal end and said lower distal end to permit said lower flexible coupler member to extend therethrough; a lower proximal mating feature on said lower proximal end; a lower distal mating feature on said lower distal end, wherein said lower proximal mating feature on each said lower vertebra member is configured to movably interface with said lower distal mating feature on an adjacent said lower vertebra member; and a lower vertebra drive feature configured to operably engage said rotary drive member.
 8. The surgical instrument of claim 7, wherein said lower proximal mating feature comprises a lower concave recess in said lower proximal end of said lower vertebra body portion, wherein said lower distal mating feature comprises a lower convex protrusion on said lower distal end of said lower vertebra body portion, and wherein said lower convex protrusion on each said lower vertebra member is sized and shaped to matingly engage said lower concave recess in said adjacent said lower vertebra member.
 9. The surgical instrument of claim 7, wherein each said upper vertebra drive feature comprises an upper tooth configured to interface with said rotary drive member, and wherein each said lower vertebra drive feature comprises a lower tooth configured to interface with said rotary drive member.
 10. The surgical instrument of claim 9, wherein said rotary drive member comprises: a rotary body portion; and a helical drive member on an external surface of said rotary body portion, wherein said helical drive member is configured to engage an upper helical surface formed on each said upper tooth and a lower helical surface on each said lower tooth.
 11. The surgical instrument of claim 10, wherein said upper helical surface comprises two different pitches.
 12. The surgical instrument of claim 3, further comprising: an upper vertebra biaser configured to apply a continuous upper compression to said upper series of upper vertebra members to retain said upper series of upper vertebra members in movable contact with each other; and a lower vertebra biaser configured to apply a continuous lower compression to said lower series of lower vertebra members to retain said lower series of lower vertebra members in movable contact with each other.
 13. The surgical instrument of claim 4, wherein said upper flexible coupler member and said lower flexible coupler member are configured to retract said firing member from a position that is distal to said starting position by applying retraction motions to each of said upper flexible coupler member and said lower flexible coupler member in a proximal direction.
 14. The surgical instrument of claim 3, wherein said articulation joint comprises an articulation joint length, wherein said upper series of upper vertebra members comprises an upper series length that is greater than or equal to the articulation joint length plus a distance from said starting position to said ending position of said firing member, and wherein said lower series of lower vertebra members comprises a lower series length that is greater than or equal to the articulation joint length plus said distance from said starting position to said ending position of said firing member.
 15. The surgical instrument of claim 14, further comprising: an upper sleeve extending from a proximal end of said surgical end effector and spanning said articulation joint, wherein said upper sleeve is axially movable relative to said surgical end effector and is configured to slidably support a portion of said upper series of upper vertebra members that spans said articulation joint; and a lower sleeve extending from said proximal end of said surgical end effector and spanning said articulation joint, wherein said lower sleeve is axially movable relative to said surgical end effector and is configured to slidably support another portion of said lower series of lower vertebra members that spans said articulation joint.
 16. A surgical instrument, comprising: an elongate shaft; a surgical end effector coupled to said elongate shaft by an articulation joint, wherein said articulation joint is configured to facilitate selective articulation of said surgical end effector relative to said elongate shaft, and wherein said surgical end effector comprises a firing member supported for axial travel within said surgical end effector between a starting position and an ending position; a rotary drive member rotatably supported distal to said articulation joint; an upper longitudinally-segmented nut assembly attached to a top portion of said firing member, wherein said upper longitudinally-segmented nut assembly is in threaded engagement with said rotary drive member at an upper location that is distal to said articulation joint such that rotation of said rotary drive member causes said upper longitudinally-segmented nut assembly to apply an upper axial drive motion to said firing member, and wherein said upper longitudinally-segmented nut assembly is flexible to accommodate said articulation of said surgical end effector; and a lower longitudinally-segmented nut assembly attached to a bottom portion of said firing member, wherein said lower longitudinally-segmented nut assembly is in threaded engagement with said rotary drive member at a lower location that is distal to said articulation joint such that rotation of said rotary drive member causes said lower longitudinally-segmented nut assembly to apply a lower axial drive motion to said firing member, and wherein said lower longitudinally-segmented nut assembly is flexible to accommodate said articulation of said surgical end effector.
 17. The surgical instrument of claim 16, wherein said upper longitudinally-segmented nut assembly comprises an upper series of upper vertebra members, wherein said upper vertebra members are movably supported relative to each other by an upper flexible coupler member that is coupled to said top portion of said firing member and extends through each said upper vertebra member, wherein said lower longitudinally-segmented nut assembly comprises a lower series of lower vertebra members, and wherein said lower vertebra members are movably supported relative to each other by a lower flexible coupler member that is coupled to said bottom portion of said firing member and extends through each lower vertebra member.
 18. The surgical instrument of claim 17, wherein said rotary drive member comprises a helical thread comprising at least two different pitches.
 19. The surgical instrument of claim 17, further comprising means for permitting said upper vertebra members and said lower vertebra members traversing said articulation joint to move out of axial alignment while facilitating serial threaded engagement with said rotary drive member.
 20. A surgical instrument, comprising: an elongate shaft; a surgical end effector comprising a firing member moveable between a starting position and an ending position; an articulation joint, wherein said surgical end effector is rotatable relative to said elongate shaft about said elongate shaft; an upper flexible spine assembly coupled to a top portion of said firing member; a lower flexible spine assembly coupled to a bottom portion of said firing member; and a rotary drive member operably interfacing with said upper flexible spine assembly and said lower flexible spine assembly distal to said articulation joint, wherein said upper flexible spine assembly and said lower flexible spine assembly are configured to move said firing member between said starting position and said ending position, based on rotation of said rotary drive member. 